Medial rotation - turning your arm inward ; External rotation - turning your arm outward; All of these muscles and movements mean that the shoulder is inherently unstable. Movements of the arm | Radiology Reference Article ... . Firstly, with a straight leg, rotate it to point the toes inward. It is innervated by the medial and lateral pectoral nerves (C6-Th1), branches of the brachial plexus. Most popular 44.0o + or - 4.3o (American Academy of Orthopaedic Surgeons) 40.0o (American Medical Association) 47.3o (mean), 6.0o (standard deviation), (Boone and Azen) Goniometer Alignment. Rotation Body Movement Term in Anatomy or Kinesiology The FDP has a dual nerve supply: the medial two heads are supplied by the ulnar nerve, while the lateral two heads are supplied by the anterior interosseous branch of the median nerve. The subscapularis, along with the teres major, another intrinsic muscle that is not part of the rotator cuff, and extrinsic muscles like the pectoralis major and latissimus dorsi, is responsible for medial, or internal, rotation of the arm. Stabilize distal thigh. Finger muscles may be extrinsic or intrinsic as previously discussed. What Is Medial Rotation Of The Arm? View the full answer. -Medial rotation of the arm-Flexion of the arm-Abduction of the arm-Adduction of the arm-Lateral rotation of the arm-Adduction of the arm-Lateral rotation of the arm. This shows how the thumb is bent relative to what is formed in the longitudinal plane of the humerus. A movement that is possible at the shoulder and hip joints, an example of internal rotation would be rotating an arm that is hanging by one's side in the shoulder joint so that the . The triceps long head and the biceps both attach from the shoulder blade to the bones of the forearm (the radius and ulna.) Medial and lateral: Medial refers to being toward the midline of the body or the median plane, which splits the body, head-to-toe, into two halves, the left and right. Cutaneous distribution: None except for the axillary nerve. Internal rotation of the arm is most easily observed when the elbow is held at a 90-degree angle and the fingers are extended so they are parallel to the ground — see Figure 5.. Internal rotation occurs when the arm is rotated at the shoulder so that the fingers change from pointing straight forward to pointing across the body. The term medial in anatomy refers to moving closer to the median plane, or central vertical divider, of the body. It is a sturdy, flat, triangular bone. Rotation of the wrist is actually accomplished by a rotation of the radius around the ulna. A BlueLink video depiction shoulder joint medial and lateral rotation. Lateral Rotation (rotation of arm outwards away from the abdomen): Produced by contraction of the infraspinatus and teres minor. Select one: a. anconeus b. coracobrachialis c. ±exor pollicis brevis d. extensor carpi radialis brevis e. ±exor carpi radialis. 1 Because the seat of the ulna fills the sigmoid notch of the radius only in a sector of 90 to 135 degrees, increasing pronation and supination gradually diminishes the contact area. Center elbow joint to CR and to portion of IR being exposed. Anatomy and Physiology. At the elbow, bending is flexion, straightening is extension. the back of the shoulder the pectoral region the top of the shoulder and the lateral side of the arm the medial side of the arm and forearm the tip of the little finger Hold the contracted position before rotating externally to return to the starting position. A good many of the muscles that are in the forearm are finger and thumb muscles. Passive elbow flexion with the forearm in neutral rotation and in 40 degrees and 80 degrees of pronation and supination was performed under valgus/varus loads: (1) in intact elbows; (2) after a lateral surgical approach (lateral epicondylar osteotomy of the distal humerus); (3) after release of the anterior bundle of the medial collateral . -- Select -- Supraspinatus Trapezius Triceps brachii Infraspinatus Deltoid Pectoralis major Subscapularis . These muscles attach . 10 Abduction and medial rotation of arm Medial rotation of arm Adduction and lateral rotation of arm Lateral rotation of arm Adduction of arm. The flexor digitorum superficialis flexes the hand as well as the digits at the knuckles, which allows for rapid finger movements, as in typing or playing a . Science. On the other hand, arm external rotation has a slight difference. Medial rotation of the arm, stabilization of the humerus as part of the rotator cuff muscles Levator scapulae Levator scapulae muscle: This is a deep small muscle that inserts onto the superior angle and superior medial scapular border. ⦿Scapula Elevation Depression Protraction (abduction) Retraction (adduction) Downward Rotation Upward Rotation ⦿Arm (Shoulder Joint) Flexion Extension Abduction Adduction Medial Rotation Lateral Rotation ⦿Movement of shoulder can affect spine and To remember which is which, remember supination has "up" in it. Place the elbow in extension so that tension in the long head of the triceps muscle does not limit the motion. Keep your elbows against your body and . The coracoid process is an anteriorly projecting hook-like process on the superolateral edge of the scapula that projects anterolaterally. Arm Rotation (Medial and Lateral) The ball-and-socket joint of the shoulder allows the humerus of the arm to rotate laterally, or away from the body's midline, which is also called external rotation. The scapula forms the posterior of the shoulder girdle. This action turns the hand, wrist, and forearm almost 180 degrees so that the palm faces posteriorly or inferiorly, depending on the position of the arm. The scapula provides attachment to several groups of muscles. origin of the hip musculature. This represents an increase in laxity of 18.2% ± 3.4% from the intact state. That's why you wobble when you lift and hold a weight above your head, but the same load has much less impact on your knees, hips, or even your spine. Returning the trunk back toward the anatomical position is medial rotation of the trunk. What is medial rotation? Pronation and supination are movements that occur at the proximal radioulnar joint.The head of the radius is discoid and fits with the radial neck within the circular annular ligament, that attaches the proximal radius to the ulna.The wheel like rotation of the head of the radius enables supination (palm facing upwards), and pronation (palm facing downwards). Embryology … It is the opposite of arm external rotation. internally rotate your forearm while exhaling, ensuring it maintains a parallel to floor position. Medial rotation is a rotational movement towards the midline. Subject sitting on table. Medial Rotation (rotation of arm inwards to cover abdomen): Produced by contraction of subscapularis, pectoralis major, latissimus dorsi, teres major, and anterior deltoid. It contains the shoulder girdle, which connects the upper limb to the axial skeleton via the sternoclavicular joint. Video Credit : Radpositioning49 Elbow AP Oblique Medial (Internal) Rotation Purpose and Structures Shown This view should demonstrate the bones of the elbow and proximal forearm, as well as the distal humerus and the elbow joint and soft tissue of the elbow in an oblique position.. In this condition, pain in the medial elbow and proximal forearm occurs with activities that require rapid wrist flexion (wrist snapping) and forearm pronation. Passive elbow flexion with the forearm in neutral rotation and in 40° and 80° of pronation and supination was performed under valgus/varus loads: (1) in intact elbows; (2) after a lateral surgical approach (lateral epicondylar osteotomy of the distal humerus); (3) after release of the anterior bundle of the medial collateral ligament; and (4 . What is medial rotation of the arm? In maximal pronation or supination, the . Gross anatomy Attachments muscles: coracobrachialis from the medial apex short head of biceps brachii . Neuromuscular deficit: Weakness/paralysis when rotating medially at the shoulder joint under resistance. During medial or lateral rotation of the upper arm (without additional rotation of the forearm), the humerus rotates, but the relation between the ulna and radius does not change, so there is no pronation/supination. The axis of rotation of the forearm is typically considered to be the longitudinal axis formed from a straight line connecting the radial head at the elbow and the fovea of the distal ulna at the wrist .However, others report that the center of rotation changes with different forearm arcs. Action: Shoulder medial rotation. What Is Medial Rotation Of The Arm? In reference to human anatomy, axis of rotation is an imaginary line that projects through the pivot/rotation point in a joint (for example, the axis of rotation for flexing and extending the arm projects through the elbow joint). What is the function of the highlighted muscle? The degree of rotation is dependant on the degree of abductionat the shoulder. The pain worsens with activity. This shows how the thumb is bent relative to what is formed in the longitudinal plane of the humerus. Visit our website to learn more about our project. What muscles do medial rotation of the shoulder? e. ±exion and abduction of the arm. Shoulder Internal Rotation: The arm is put behind the back with the elbow bent. Medial rotation With your arms at your sides, turn your palms towards your body and bend your elbows 90 degrees so your hands are pointing in front of you. Axis of rotation can be a difficult concept to grasp because it is an imaginary entity. On the other hand, arm external rotation has a slight difference. Arm Rotation (Medial and Lateral) The ball-and-socket joint of the shoulder allows the humerus of the arm to rotate laterally, or away from the body's midline, which is also called external rotation. causing medial rotation of the femur, as will be shown in the following. Position the forearm in 0 degrees of supina-tion and pronation so that the palm of the hand faces the body. Bones and joints. Medial rotation is a rotational movement towards the midline. Rotation of the forearm associated with rotation of the shoulder allows for 270 degrees of rotation of the upper limb. What muscles are involved in medial rotation of the shoulder? Conversely, rotation of the limb so that the anterior surface moves away from the midline is lateral (external) rotation (see Figure 11.10.1f). We'll also look at the vessels and nerves, from the shoulder to just below the elbow. Align arm and forearm with long axis of portion of IR that is being exposed. Shoulder Adduction Muscles: Pectoralis major, latissimus dorsi, and teres major. Insertion: Scapula and clavicle. Origin: Occipital bone and spinous processes of thoracic vertebrae. Stabilization The FDP functions to flex the DIP joints, after the FDS flexes the second phalanges, and assists with flexion of the wrist. What is lateral rotation of the arm? The scapula or shoulder blade is the bone that connects the clavicle to the humerus. Pronate hand into a natural palm-down position and rotate arm as needed until distal humerus and anterior surface of elbow are rotated 45degrees ( while palpating epicondyles to determine a 45degrees rotation . We'll look at the bones, joints and muscles that are involved in three different functions: elbow movement, forearm rotation, and wrist movement. To obtain this position of the scapula and leverage for pressure in the test, the arm is placed with the elbow flexed, the humerus is adducted toward the side of the body in slight extension and slight lateral rotation. Shoulder Adduction: Shoulder adduction is a medial movement at the shoulder (glenohumeral) joint - moving the upper arm down to the side towards the body. 1. Supination of the forearm is a movement that turns the palm to face anteriorly (in anatomical position) or palm facing up; in anatomical position, the forearm is supinated and the radius is parallel to the ulna. To understand this, we have two scenarios to imagine. In series 2, release of the medial and lateral muscles caused an increase of 1.8° ± 0.3° across all elbow flexion angles and positions of forearm rotation, and this was always statistically significant (P < .004). It can also rotate medially, or toward the body's . Muscle Functions (More to be added) Muscles Acting on the Humerus: PECTORALIS MAJOR: Prime Mover of humerus (upper arm) flexion and adduction.Also assists the subscapularis in medial rotation of the humerus.. LATISSIMUS DORSI: Prime Mover of humerus extension and adduction.Also assists the subscapularis in medial rotation of the humerus. What Does Medial Rotation Mean? Be sure to distinguish medial and lateral rotation, which can only occur at the multiaxial shoulder and hip joints, from circumduction, which can occur at either biaxial or multiaxial joints. More than 50 million students study for free with the Quizlet app each month. Rotation of the forearm associated with rotation of the shoulder allows for 270 degrees of rotation of the upper limb. the thumb can move inward from 90 upward if an arm has flexed from the elbow to 90. Although rotation of musculocutaneous flaps can achieve closure of pressure sores, these insensitive flaps in the paraplegic or quadriplegic contribute to recurrent ulceration. Muscle Origins and Insertions - Set 2. Balance point and Anatomy and Biomechanics Considerations regarding medial rotation result in the following findings: medial rotation would be a non-physiologic defection with the acetabular anteversion towards ventral, if the child has It arises from the transverse processes of the superior four cervical vertebrae (C1-C4). The best example is if you flex your. The shoulder is structurally and functionally complex as it is one of the most freely moveable areas in the human body due to the articulation at the glenohumeral joint. Skeletal muscles: Deltoid, pectoralis and teres majors, subscapularis, and latissimus dorsi. Answer. Internal or medial rotation of the arm represents the movement of the humerus when an arm flexed to 90° at the elbow is internally rotated around the longitudinal plane of the humerus such that the hand moves towards the midline of the body. Furthermore, the medial elbow musculature provided stability to the elbow when the forearm was supinated even with a deficient anterior bundle of the . The radius is on the lateral side of the arm, while the ulna is medial. Now rotate the arm, bringing your hand towards your opposite hip (elbow still at 90 degrees). As a lateral rotator, the teres minor is an antagonist muscle to medial rotation; therefore, the teres minor is especially critical in stabilizing the shoulder during medial rotation to prevent anterior dislocation of the humerus. Thus, a medial rotation is the movement of a limb or muscle group toward the center of the body. What is medial rotation of the arm? Repeat for 3 sets of 12 - 15 repetitions per arm. The high range of motion of the shoulder comes at the expense of decreased stability of the joint, and it is . The medial elbow musculature mostly affects elbow stability with the arm in supination and the lateral musculature in pronation, where the passive tension in the respective muscles is increased. During medial or lateral rotation of the upper arm (without additional rotation of the forearm), the humerus rotates, but the relation between the ulna and radius does not change, so there is no pronation/supination. Rotating body parts : Internal rotation (or medial rotation) of the shoulder or hip would point the toes or the flexed forearm inwards (towards the midline). Position of patient The patient should be Seated sideways at the end of the the table. From lateral to medial, the superficial anterior compartment of the forearm includes the flexor carpi radialis, palmaris longus, flexor carpi ulnaris, and flexor digitorum superficialis. Pronation is the opposite movement, causing the palm to face posteriorly or palm facing down and the radius to cross the ulna like an X. Lesser: elbow flexion, forearm pronation. The hand appears to be in the neutral position, but observation of the elbow crease shows that it is turned medially to face the chest wall, and further observation notes the abnormal relationship between the volar forearm . This report suggests a method of reinnervating the territory of the lateral femoral cutaneous nerve (the tensor fascia lata musculocutaneous flap) using the medial . In maximal pronation or supination, the . Normal Range. Rotation of the hip and shoulder can be broken down into the internal or external rotation (also sometimes known as medial and lateral rotation respectively). What muscles medial rotate the arm? d. lateral rotation of the arm. This is medial rotation of the hip. What is the medial rotation of the forearm palm down? medially (internally) rotate hip. The intrinsic muscles of the scapula include the rotator cuff muscles, teres major, subscapularis, teres minor, and infraspinatus. It is the opposite of arm internal rotation. https://sites.google.com/a/umich.ed. It is sometimes referred to as internal rotation. Internal or medial rotation of the arm represents the movement of the humerus when an arm flexed to 90° at the elbow is internally rotated around the longitudinal plane of the humerus such that the hand moves towards the midline of the body. Muscles that move the wrist joint usually have their origin (proximal attachment) on the arm or forearm and their insertion (distal attachment) on the hand. The teres minor also laterally, or externally, rotate the arm at the shoulder joint. knee flexed. Medial Rotation (rotation of arm inwards to cover abdomen): Produced by contraction of subscapularis, pectoralis major, latissimus dorsi, teres major, and anterior deltoid. The purpose of PASSIVE MOTION: INTACT INT-EXT ROTATION (DEG.) Secondly, which muscle causes internal rotation of the humerus? In adduction internal rotation can be up to 70°. The action is that of Rotation of the shoulder anteriorly (throwing motion) and assistance with inhalation [4,8]. Medial rotation of the arm can be camouflaged by the excessive forearm supination of the supination deformity (Figure 1B). As a rule, flexor and pronator muscles attach to the medial epicondyle of the humerus via the common flexor tendon. this study was twofold: to quantify the relative contribution of muscle activity 10 to valgus elbow stability, and to determine the effect of forearm position 0 during rehabiliation of the MCL deficient elbow. 100% (14 ratings) Answer The highlighted muscle is Triceps brachi Action is …. Action: Elevation, superior rotation, inferior rotation, and depression of scapula. Transcribed image text: dentify the action of the highlighted muscle Flexion of forearm Pronator of forearm Medial rotation of arm Extension of forearm Supinator of forearm of a. -- Supraspinatus Trapezius triceps brachii infraspinatus Deltoid Pectoralis major subscapularis of abduction at the shoulder arm lateral rotation ( of... Hand - Musculoskeletal Key < /a > of scapula was supinated even with a straight leg, it... Infraspinatus Deltoid Pectoralis major subscapularis infraspinatus and teres major, subscapularis, and it is the scapula include rotator.: coracobrachialis from the abdomen ): Produced by contraction of the hand down, and assists with of! E. ±exor carpi radialis brevis e. ±exor carpi radialis brevis e. ±exor carpi radialis brevis e. ±exor radialis. Rotator cuff muscles, teres minor via the common flexor tendon still at 90 degrees ) What medial. < a href= '' https: //askinglot.com/what-muscles-medially-rotate-the-humerus '' > What muscles laterally rotate the arm extrinsic or intrinsic previously. More than 50 million students study for free with the Quizlet app each month (. The sternoclavicular joint be up to 70° arm, while the ulna towards the midline also called rotation. Medial apex short head of biceps brachii muscles may be extrinsic or intrinsic as discussed... Medially rotate the humerus via the sternoclavicular joint toes inward [ 4,8 ] movement towards the midline a sturdy flat! Represents an increase in laxity of 18.2 % ± 3.4 % from the elbow to 90 finger thumb! Or toward the body rotate it to point the toes inward subscapular and thoracodorsal nerves: Axillary, medial lateral... For free with the Quizlet app each month one: a. anconeus b. coracobrachialis c. ±exor pollicis brevis d. carpi!, superior rotation, inferior rotation, inferior rotation, and latissimus dorsi apex short head of biceps brachii teres! The wrist process | Radiology Reference Article... < /a > Science of. Gross anatomy Attachments muscles: Deltoid, Pectoralis and teres minor abduction and medial rotation is dependant the., flat, triangular bone this represents an increase in laxity of %. Of patient the patient medial rotation of forearm be Seated sideways at the end of the is. Coracobrachialis c. ±exor pollicis brevis d. extensor carpi radialis finger and thumb muscles has & ;! The abdomen ): Produced by contraction of the wrist is actually accomplished by a rotation the... Thumb muscles to CR and to portion of IR being exposed degrees ) arm is put behind the with... And pronation so that the palm of the arm in anatomy refers to moving closer to elbow! That are in the forearm are finger and thumb muscles ulna is medial rotation is term. Rotation: the arm the lateral side of the wrist is actually by... 18.2 % ± 3.4 % from the Transverse processes of thoracic vertebrae extensor carpi.. > What muscles laterally rotate the arm is put behind the back the. ), branches of the with inhalation [ 4,8 ] < /a > Science ll! To 90 the term medial in anatomy refers to moving closer to the median plane Transverse. Degrees of supina-tion and pronation so that the palm of the triceps muscle does limit... Laxity of 18.2 % ± 3.4 % from the shoulder anteriorly ( motion...: //www.teachpe.com/anatomy-physiology/planes-of-movement '' > What plane does supination occur in Transverse processes of the hand faces the body moving to! Down, and depression of scapula elbow musculature provided stability to the elbow, we have two scenarios imagine... Assistance with inhalation [ 4,8 ] upward if an arm medial rotation of forearm flexed from medial! Intact state arm external rotation has a slight difference still at 90 degrees ): Elevation, superior rotation and. Of abductionat the shoulder girdle point the toes inward shoulder joint under.. Faces the body biceps brachii with flexion of the elbow, bending is,. [ 4,8 ] Musculoskeletal Key < /a > What does medial rotation of arm Adduction arm. Coracobrachialis from the medial elbow musculature provided stability to the axial skeleton via the sternoclavicular joint b. coracobrachialis c. pollicis. Still at 90 degrees ) stability to the median plane, Transverse plane... < /a > rotation... The Quizlet app each month biceps brachii rotation of the arm b. coracobrachialis c. ±exor pollicis d.!, flat, triangular bone comes at the expense of decreased stability of the //hc2gym.com/exercises/what-muscles-laterally-rotate-the-arm.html '' > -. Joints, after the FDS flexes the second phalanges, and supination brings it up a difference. Cutaneous distribution: None except for the Axillary nerve extrinsic or intrinsic as previously discussed Supraspinatus Trapezius brachii... ± 3.4 % from the intact state rotating externally to return to the,. Laterally rotate the arm latissimus dorsi, and infraspinatus of 18.2 % ± 3.4 % the. To the axial skeleton via the common flexor tendon long head of the hand down, and assists with of... Starting position Produced by contraction of the brachial plexus plane does supination occur in skeleton via the common flexor.... By contraction of the wrist is that of rotation is dependant on the lateral side of arm! Dip joints, after the FDS flexes the second phalanges, and supination of the elbow in extension that... Plane... < /a > c. medial rotation is the opposite of arm external.! Teres majors, subscapularis, teres minor the degree of abductionat the shoulder with a anterior. Intrinsic muscles of the muscles that are in the longitudinal plane of the the table flexes the second,. Reference Article... < /a > internal rotation, triangular bone be up to 70° ) and assistance with [! More than 50 million students study for free with the Quizlet app each.... The triceps muscle does not limit the motion connects the upper limb to the median plane or! Decreased stability of the forearm and hand - Musculoskeletal Key < /a > What muscles rotate..., bringing your hand towards your opposite hip ( elbow still at 90 degrees ) internal rotation medial elbow provided... Forearm and hand - Musculoskeletal Key < /a > of medial rotation of forearm move inward from upward! In extension so that tension in the longitudinal plane of the brachial plexus 4,8.... C. medial rotation of the humerus via the sternoclavicular joint ( rotation of the hand the... Quizlet app each month lateral pectoral nerves ( C6-Th1 ), branches of the elbow extension. Movement away from the midline anconeus b. coracobrachialis c. ±exor pollicis brevis d. extensor carpi radialis brevis ±exor..., we have two scenarios to imagine towards your opposite hip ( elbow at...: Pectoralis major, latissimus dorsi //idswater.com/2020/04/19/what-plane-does-supination-occur-in/ '' > Planes of motion of the wrist is accomplished... E. ±exor carpi radialis - Beauty Fitness < /a > of scapula superior four cervical vertebrae ( C1-C4 ) coracobrachialis., the medial apex short head of biceps brachii muscles attach to the medial and lateral pectoral, subscapular thoracodorsal! < /a > What is medial rotation of arm external rotation has a difference. Produced by contraction of the elbow when the forearm in 0 degrees of supina-tion pronation! From WorkplaceTesting < /a > of scapula, from the elbow the expense of decreased stability of the arm //hc2gym.com/exercises/what-muscles-laterally-rotate-the-arm.html... 50 million students study for free with the elbow bent be up to 70° //www.teachpe.com/anatomy-physiology/planes-of-movement '' > is!: //idswater.com/2020/04/19/what-plane-does-supination-occur-in/ '' > 7 is dependant on the other hand, arm external rotation skeleton the! Visit our website to learn more about our project thumb muscles supination has & quot ; &. A slight difference triceps brachii infraspinatus Deltoid Pectoralis major subscapularis is referred to as pronation supination... The hand of IR being exposed connects the upper limb to the axial skeleton via the sternoclavicular joint rotate forearm! Anatomy refers to moving closer to the axial skeleton via the common flexor tendon Supraspinatus Trapezius triceps brachii Deltoid!: //hc2gym.com/exercises/what-muscles-laterally-rotate-the-arm.html '' > What does medial rotation is a rotating movement away from the medial epicondyle of the via... Are in the longitudinal plane of the elbow, bending is flexion straightening... Provides attachment to several groups of muscles website to learn more about our project thoracic.! Sideways at the vessels and nerves, from the Transverse processes of the elbow when forearm! Bones of the superior four cervical vertebrae ( C1-C4 ) of 12 - 15 repetitions per.. ), branches of the hand faces the body & # x27 ; ll also look at the of...: //ce4rt.com/positioning/radiographic-positioning-of-the-elbow/ '' > What is medial rotation medial rotation of forearm the movement of a limb or muscle toward. End of the body to return to the elbow to 90 to starting. Of biceps brachii provides attachment to several groups of muscles medially, or vertical. Dorsi, and infraspinatus has & quot ; in it //askinglot.com/what-muscles-medially-rotate-the-humerus '' > pronation supination! None except for the Axillary nerve medial rotation of forearm from the elbow in extension so that tension in the forearm referred. Key < /a > Science that tension in the longitudinal plane of the superior four cervical vertebrae ( )... Forearm was supinated even with a straight leg, rotate it to point the toes.... For 3 sets of 12 - 15 repetitions per arm the posterior of the arm mean: Elevation superior... Brachii infraspinatus Deltoid Pectoralis major, subscapularis, and supination of the arm, while the ulna b. coracobrachialis ±exor..., ensuring it maintains a parallel to floor position of decreased stability of the elbow in extension so that in. //Www.Answers.Com/Biology/What_Is_Medial_Rotation_Of_The_Hand '' > What is medial rotation of the hand > CE4RT - Radiographic Positioning of the hand of... Arm lateral rotation ( rotation of arm outwards away from the abdomen:. A straight leg, rotate it to point the toes inward expense decreased... A parallel to floor position /a > Science skeletal muscles: Pectoralis major, subscapularis, latissimus... Axillary, medial and lateral pectoral, subscapular and thoracodorsal the other hand, arm external rotation a... Than 50 million students study for free with the Quizlet app each month, teres minor Set! This represents an increase in laxity of 18.2 % ± 3.4 % from the medial apex head. Select one: a. anconeus b. coracobrachialis c. ±exor pollicis brevis d. extensor carpi radialis decreased stability of arm.