UNIT 3 (SHOULDER COMPLEX).pdf

School of Nursing and Allied Health Diploma in Physiotherapy Program FUNCTIONAL ANATOMY OF UPPER EXTREMITY...

School of Nursing and Allied Health Diploma in Physiotherapy Program FUNCTIONAL ANATOMY OF UPPER EXTREMITY (PTAU 4113) UNIT 3 : SHOULDER JOINT Prepared by, Vaneeyshaa Chandran M.PT(MY),B.PT(MY/UK), D.PT(MY) 28/08/2024  Lesson Learning Outcome At the end of the lesson the students should be able to: State the bones of the upper limb. Identify the bones and bony prominences of the upper limb. Identify the fossa and the ridges on the surfaces of the bone.  3.1 Osteology and arthrology of clavicle, scapula, humerus Pectoral (Shoulder) Girdle The pectoral girdle or shoulder girdle is the set of bones which connects the upper limb to the axial skeleton on each side. Shoulder Complex : consists of the clavicle and scapula and glenohumeral joint (shoulder joint). The shoulder is highly mobile, allowing a wide range of motion at the expense of stability. Key to upper limb function in activities such as lifting, pushing, and throwing.  3.1 Osteology and arthrology of clavicle, scapula, humerus Clavicle Anterior bone, that articulates with manubrium of the sternum forming a sternoclavicular joint. S-shaped clavicle (slender) Aka “collarbone” Lies anterior part of the thorax, superior to the first rib.  3.1 Osteology and arthrology of clavicle, scapula, humerus Clavicle (Features) It is subcutaneous (under the skin) and easily palpable along its length. Why S-shape? Medial half is convex anteriorly (curves towards you when view in anatomical position) Lateral half is concave anteriorly (curves away from you) It is found to be rougher and more curved in males. 3.1 Osteology and arthrology of clavicle, scapula, humerus Clavicle The medial end (sternal end) is rounded and articulates with manubrium of the sternum to form the sternoclavicular joint. The lateral end (broad and flat, aka acromial end) articulates with the acromion of scapula to form acromioclavicular joint. 3.1 Osteology and arthrology of clavicle, scapula, humerus Clavicle The conoid tubercle on the inferior surface of the lateral end of the bone is a point of attachment for coronoid ligament; Which attaches the clavicle and scapula At the impression for the costoclavicular ligament (inferior surface of the sternal end) is a point of attachment for costoclavicular ligament; which attaches clavicle and first rib.  3.1 Osteology and arthrology of clavicle, scapula, humerus Fun Fact about Clavicle only long bone that is placed horizontally It is subcutaneous throughout First bone to ossify in the body Generally said to have no medullary cavity (no bone marrow) Rotatory movements are present in the clavicle. 3.1 Osteology and arthrology of clavicle, scapula, humerus  3.1 Osteology and arthrology of clavicle, scapula, humerus Scapula Aka “shoulder blade” Large, triangular, flat bone Situated at the superior part of the posterior thorax between the levels of the second and seventh ribs  3.1 Osteology and arthrology of clavicle, scapula, humerus Scapula (features) A prominent ridge called the spine runs diagonally across the posterior surface of the scapula. The lateral end of the spine projects as a flattened, expanded process called the acromion Easily felt as high point of shoulder  3.1 Osteology and arthrology of clavicle, scapula, humerus Scapula (features) Inferior to acromion is a shallow depression, the glenoid cavity, that accepts the head of humerus (arm bone) to form the glenohumeral (shoulder joint). Thin edge of scapula closer to the vertebrae column is called as the medial (vertebral border) Thick edge of the scapula closer to the arm is called the lateral (axillary) border.  3.1 Osteology and arthrology of clavicle, scapula, humerus Scapula (features) The medial and lateral borders join at the inferior angle. Superior edge of scapula, called the superior border, joints the medial border at the superior angle. Scapular notch – prominent indentation along the superior border (which the suprascapular nerve passes).  3.1 Osteology and arthrology of clavicle, scapula, humerus Scapula (features) Lateral end of the superior border of the scapula is a projection of the anterior surface called the coracoid process (like a crow’s beak) Which the tendons of muscles and ligaments attach. Superior and inferior to the spine on the posterior surface of the scapula are two fossae; Supraspinous fossa – a surface of attachment for the supraspinatus muscle of the shoulder Infraspinous fossa – a surface of attachment for the infraspinatus muscle of the shoulder Anterior surface of scapula (slightly hollowed-out area) called the subscapular fossa (a surface attachment for subscapularis muscle). 3.1 Osteology and arthrology of clavicle, scapula, humerus 3.1 Osteology and arthrology of clavicle, scapula, humerus Anterior Scapula Surface markings acromion process coracoid process glenoid cavity superior angle subscapular fossa inferior angle Posterior Scapula Surface markings acromion process supraspinous fossa infraspinous fossa Spine of scapula lateral border medial border  3.1 Osteology and arthrology of clavicle, scapula, humerus Upper Limb (Upper Extremity) Has 30 bones in 3 location: 1. Humerus in the arm 2. Ulna and radius in the forearm 3. Carpus (Wrist) 8 Carpals in the wrist 5 Metacarpals in the metacarpus (palm) 14 phalanges (bones of the digits) in the hand The bones of Upper limb are discussed next  3.1 Osteology and arthrology of clavicle, scapula, humerus Humerus Arm bone Longest and largest bone of upper limb Proximally – articulates with scapula Distally – articulates with ulna and radius (forms elbow joint)  3.1 Osteology and arthrology of clavicle, scapula, humerus Humerus (Features) Proximal of humerus (rounded head) articulates with glenoid cavity of scapula to form Glenohumeral (shoulder) joint. Distal to head is the anatomical neck (visible as an oblique groove). Former site of the epiphyseal (growth) plate in an adult humerus.  3.1 Osteology and arthrology of clavicle, scapula, humerus Humerus (Features) Greater tubercle – lateral projection distal to the anatomical neck. Most laterally palpable bony landmark of the shoulder region And immediately inferior to palpable acromion of scapula. Lesser tubercle – projects anteriorly Intertubercle sulcus – is a groove found between greater and lesser tubercle. Surgical neck – a constriction in the humerus just distal to tubercles Name after site for fracture  3.1 Osteology and arthrology of clavicle, scapula, humerus Humerus (Features) The body (shaft) of the humerus is roughly cylindrical at its proximal end, but gradually becomes triangular until is it flattened and broad at its distal end. Deltoid tuberosity – laterally, at medial portion of the shaft Appears roughened, V-shaped area Serves as point of attachment for tendons of deltoid muscles. Radial groove – posterior surface of humerus, runs along the deltoid tuberosity Contains radial nerve  3.1 Osteology and arthrology of clavicle, scapula, humerus Humerus (Features) Prominent features at distal end of humerus: Capitulum (capit = head) Rounded knob on the lateral aspect of the bone that articulates with head of radius. Radial fossa (capit = head) Anterior depression above the capitulum that articulates with head of the radius (when forearm is flexed). Trochlea Medial to capitulum Spool-shaped surface that articulates with trochlear notch of ulna  3.1 Osteology and arthrology of clavicle, scapula, humerus Humerus (Features) Prominent features at distal end of humerus: Coronoid fossa (crown-shaped) Anterior depression that receives the coronoid process of the ulna when the forearm is flexed. Olecranon fossa (elbow) Large posterior depression that receives the olecranon of the ulna when the forearm is extended. Medial and Lateral epicondyle Rough projections on either side of the distal end of the humerus to which the tendons of most muscles of the forearm are attached.  3.1 Osteology and arthrology of clavicle, scapula, humerus Humerus (Features) Prominent features at distal end of humerus: Ulnar nerve – may be palpated by rolling a finger over the skin surface above the posterior surface of medial epicondyle. This nerve is the one that makes you feel a very severe pain when you hit your elbow (commonly referred to as funnybone).  Surface anatomy Distal Humerus Surface anatomy Proximal Humerus  Distal condyle posterior view Distal condyle anterior view  Fossa and Ridges of the Shoulder Joint Scapula: Supraspinous Fossa: Above the spine of the scapula, provides origin for the supraspinatus muscle. Infraspinous Fossa: Below the spine of the scapula, provides origin for the infraspinatus muscle. Subscapular Fossa: The anterior surface of the scapula, origin for the subscapularis muscle. Humerus: Deltoid Tuberosity: A ridge on the lateral surface where the deltoid muscle attaches.  3.1 Osteology and arthrology of clavicle, scapula, humerus Joints Forms 3 anatomical (true) joints, and one physiological joint : The sternoclavicular (SC) joint → formed between the manubrium of the sternum and the sternal end of the clavicle. The acromioclavicular (AC) joint → formed by the acromion of scapula and the acromial end of the clavicle. The glenohumeral (shoulder) joint → formed between the glenoid fossa of the scapula and the head of the humerus. The scapulothoracic joint → formed between the anterior surface of the scapula and the posterior thoracic cage. → This joint is not a true joint but rather a physiological joint established by the several muscles, including the trapezius, rhomboids and serratus anterior.  3.1 Osteology and arthrology of clavicle, scapula, humerus Sternoclavicular Joint is a synovial saddle joint but functions as a “ball and socket” synovial joint. formed by the manubrium of the sternum and the sternal (proximal) end of the clavicle. the superior surface of first costal cartilage partakes in the formation of this joint by connecting with the clavicle. The SC joint is the only articulation between the upper limb and the axial skeleton, easily palpable because the sternal end of the clavicle lies superior to the manubrium of the sternum.  3.1 Osteology and arthrology of clavicle, scapula, humerus Sternoclavicular Joint Ligaments: anterior and posterior sternoclavicular ligaments interclavicular ligament costoclavicular ligament Blood supply: vascularized by the internal thoracic suprascapular arteries Nerve supply: innervated by the branches of the medial suprascapular nerve nerve to subclavius muscle  3.1 Osteology and arthrology of clavicle, scapula, humerus Sternoclavicular Joint Movements: it is significantly mobile, anterior and posterior movements of the shoulder girdle elevation and depression as well as a special form of circumduction (which is performed by moving the acromial end along a circular path)  3.1 Osteology and arthrology of clavicle, scapula, humerus Acromioclavicular Joint is a plane synovial joint formed by the acromion of scapula and the acromial (distal) end of the clavicle. is strengthened by several ligaments that span between the acromion and clavicle, as well as the coracoid process of the scapula and the clavicle or acromion.  3.1 Osteology and arthrology of clavicle, scapula, humerus Acromioclavicular Joint Ligaments: includes the acromioclavicular, trapezoid, conoid and the coracoclavicular ligament. Blood supply: vascularized by the suprascapular and thoracoacromial arteries Nerve supply: innervated by the suprascapular, lateral pectoral, and axillary nerves.  3.1 Osteology and arthrology of clavicle, scapula, humerus Glenohumeral (shoulder) joint multiaxial, ball-and-socket (synovial joint) that depends primarily on the muscles and ligaments rather than bones for its support, stability, and integrity. The labrum, which is the ring of fibrocartilage, surrounds and deepens the glenoid cavity of the scapula about 50%. This joint has three axes and three degrees of freedom.  3.1 Osteology and arthrology of clavicle, scapula, humerus Glenohumeral (shoulder) joint When relaxed, the humerus sits centered in the glenoid cavity; with contraction of the rotator cuff muscles, it is pushed or translated anteriorly, posteriorly, inferiorly, superiorly, or in any combination of these movements. This movement is small, but if it does not occur, full movement is impossible.  3.1 Osteology and arthrology of clavicle, scapula, humerus Glenohumeral (shoulder) Joint Muscles: rotator cuff muscles - play an integral role in shoulder movement. Their positioning on the humerus may be visualized by “cupping” the shoulder with the thumb anteriorly. The rotator cuff controls osteokinematic and arthrokinematic motion of the humeral head in the glenoid and along with the biceps depresses the humeral head during movements into elevation.  3.1 Osteology and arthrology of clavicle, scapula, humerus Glenohumeral (shoulder) Joint Bursae: The internal surface of the joint capsule is well lined by synovial membrane and the joint is also rich in bursae (sac-like cavities) which contain capillary films of synovial fluid secreted by the synovial membrane. Those bursae include: → Subdeltoid bursa → subacromial bursa  3.1 Osteology and arthrology of clavicle, scapula, humerus Glenohumeral (shoulder) Joint Ligaments: primary ligaments of the glenohumeral joint: → superior, middle, and inferior glenohumeral ligaments → play an important role in stabilizing the shoulder The superior glenohumeral ligament → Primary role: limiting inferior translation in adduction Also restrains anterior translation and lateral rotation up to 45° abduction.  3.1 Osteology and arthrology of clavicle, scapula, humerus Glenohumeral (shoulder) Joint The medial glenohumeral ligament → which is absent in 30% of the population → limits lateral rotation between 45° and 90° abduction  3.1 Osteology and arthrology of clavicle, scapula, humerus Glenohumeral (shoulder) Joint The inferior glenohumeral ligament → most important. → has an anterior and posterior band with a thin “axillary pouch” in between, so it acts much like a hammock or sling. → It supports the humeral head above 90° abduction, limiting inferior translation while the anterior band tightens on lateral rotation and the posterior band tightens on medial rotation. → Excessive lateral rotation (example: throwing), may lead to stretching of the anterior portion of the ligament (and capsule), thereby increasing glenohumeral laxity  3.1 Osteology and arthrology of clavicle, scapula, humerus Glenohumeral (shoulder) Joint The coracohumeral glenohumeral ligament → primarily limits inferior translation → Helps limit lateral rotation below 60° abduction. → is found in the rotator interval between the anterior border of the supraspinatus tendon and the superior border of the subscapularis tendon, → Thus, the ligament unites the two tendons anteriorly.  3.1 Osteology and arthrology of clavicle, scapula, humerus Glenohumeral (shoulder) Joint The coracohumeral glenohumeral ligament → The rotator interval consists of: fibers of the coracohumeral ligament, superior glenohumeral ligament, glenohumeral joint capsule, and part of the tendons of supraspinatus and subscapularis. Injury to these structures can lead to contractures, biceps tendon instability, and anterior glenohumeral instability. → forms an arch over the humeral head, acting as a block to superior translation.  3.1 Osteology and arthrology of clavicle, scapula, humerus Glenohumeral (shoulder) Joint The transverse humeral ligament → also known as the ligament of Brodie, → is a capsular ligament of the glenohumeral joint. → It is a broad fibrous band that extends between the greater and lesser tubercles of the humerus, forming a roof over the intertubercular sulcus (bicipital groove), converting it into a canal. → The tendon of the long head of the biceps brachii muscle travels through this canal deep to the transverse humeral ligament, which therefore prevents displacement of the tendon of the long head of the biceps brachii muscle during movements of the glenohumeral joint.  3.1 Osteology and arthrology of clavicle, scapula, humerus Glenohumeral (shoulder) Joint The capsular pattern of the glenohumeral joint is: lateral rotation most limited followed by abduction And medial rotation. Blood supply: is vascularized by the anterior and posterior circumflex humeral arteries branches of the suprascapular artery Nerve supply: Its nervous supply stems from the axillary, suprascapular, and the lateral pectoral nerves and branches of the posterior cord of the brachial plexus.  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle The glenohumeral articulation (shoulder joint) has the greatest range of motion of any joint in the body. The mobility of the shoulder joint is necessary for placement of the hand to maximize manipulation.  3.1 Osteology and arthrology of clavicle, scapula, humerus Scapulothoracic Joint not a true joint it functions as an integral part of the shoulder complex Aka “scapulocostal joint” This “joint” consists of the body of the scapula and the muscles covering the posterior chest wall. The muscles acting on the scapula help to control its movements.  3.1 Osteology and arthrology of clavicle, scapula, humerus Scapulothoracic Joint The medial border of the scapula is not parallel with the spinous processes but is angled about 3° away (top to bottom), and the scapula lies 20° to 30° forward relative to the sagittal plane. Because it is not a true joint, it does not have a capsular pattern nor a close packed position. The scapula extends from: → level of T2 spinous process to T7 or T9 spinous process → depending on the size of the scapula.  3.1 Osteology and arthrology of clavicle, scapula, humerus Scapulothoracic Joint Because the scapula acts as a stable base for the rotator cuff muscles, → The muscles controlling its movements must be strong → And balanced → because the joint funnels the forces of the trunk and legs into the arm  Osteokinematics of GH Joint Type of Movements (Glenohumeral joint) Flexion - moving the humerus forward and upward in the sagittal plane. Extension - bringing the arm down to the side in the sagittal plane. Abduction - moving the arm in the coronal plane away from the midline Stages: 1. initiate -supraspinatus 2. 90° - deltoid 3. 180 ° - deltoid with upward rotation of scapula  Osteokinematics of GH Joint Type of Movements Adduction - moving the arm in the coronal plane towards the midline. Inward Rotation (Internal Rotation) - rotating the arm in a transverse plane so that the anterior surface of the bone turns inward. Outward Rotation (External Rotation) - rotating the arm in a transverse plane so that the anterior surface of the bone turns outward. Osteokinematics of GH Joint  Osteokinematics of ST Joint Movements of Scapula Abduction(protraction) - Adduction(retraction) Elevation - Depression Medial rotation - Lateral rotation  Osteokinematics of GH Joint Horizontal plane Sagittal plane Frontal plane Osteokinematics of GH Joint Osteokinematics of ST Joint Scapulothoracic Joint  Kinematics of SC Joint Sternoclavicular Joint The osteokinematics of the clavicle involve a rotation in all three degrees of freedom. Each degree of freedom is associated with one of the three cardinal planes of motion: sagittal, frontal, and horizontal. The clavicle elevates and depresses, protracts and retracts, and rotates around the bone’s longitudinal axis (Figure 5-13). The primary purpose of these movements is to place the scapula in an optimal position to accept the head of the humerus. Kinematics of SC Joint Elevation and Depression Approximately parallel to the frontal plane, around a near anterior-posterior axis of rotation 45 degrees of elevation and 10 degrees of depression  Kinematics of SC Joint Elevation Elevation of the clavicle occurs as its convex articular surface rolls superiorly and simultaneously slides inferiorly on the concavity of the sternum. stretched costoclavicular ligament helps limit as well as stabilize the elevated position of the clavicle. Depression of the clavicle occurs by action of its convex surface rolling inferiorly and sliding superiorly. A fully depressed clavicle elongates and stretches the interclavicular ligament and the superior portion of the capsular ligaments. Kinematics of SC Joint (Protraction and Retraction) Occurs at horizontal plane, around a vertical axis of rotation A maximum of 15 to 30 degrees of motion have been reported in each direction Retraction Retraction occurs as the concave articular surface of the clavicle rolls and slides posteriorly on the convex surface of the sternum At the end ranges of retraction, it elongates the anterior bundles of the costoclavicular ligament and the anterior capsular ligaments. Protraction arthrokinematics of protraction around the SC joint are similar to those of retraction, except that they occur in an anterior direction. Occurs during a motion involving maximal forward reach. Excessive tightness in the posterior bundle of the costoclavicular ligament, the posterior capsular ligament, and the scapular retractor muscles limit the extremes of clavicular protraction. Kinematics of SC Joint Rotation rotation of the clavicle around the bone’s longitudinal axis. During shoulder abduction or flexion, a point on the superior aspect of the clavicle rotates posteriorly 20 to 35 degrees. As the arm is returned to the side, the clavicle rotates back to its original position. The arthrokinematics: involve a spin of its sternal end relative to the lateral surface of the articular disc  Kinematics of GH Joint CONCAVE – CONVEX RULE Convex moving on Concave Opposite direction of gliding and same direction of rolling.  Kinematics of GH Joint Motion at the glenohumeral joint occurs as a rolling and sliding of the head of the humerus on the glenoid fossa. The convex joint surface of the head of the humerus glides in the opposite direction and rolls in the same direction as the osteokinematic movements of the shaft of the humerus. The sliding/gliding motions help to maintain contact between the head of the humerus and the glenoid fossa of the scapular during the rolling motions and reduce translational movement of the axis of rotation in the humerus.  Kinematics of GH Joint Shoulder Abduction The convex head of humerus rolls superiorly and glides inferiorly on the concave surface of glenoid fossa. Shoulder Adduction The convex head of humerus rolls inferiorly and glides superiorly on the concave surface of glenoid fossa. Kinematics of GH Joint  Kinematics of GH Joint Shoulder Flexion a spinning motion of the convex humeral head around the concave glenoid fossa At least 120 degrees of flexion from GH joint To reach Shoulder flexion (180 degree), includes an accompanying upward rotation of the scapulothoracic joint. Shoulder Extension a spinning motion of the convex humeral head around the concave glenoid fossa Full extension - Actively reach 65 degrees and 80 degrees passively. If extremely perform passive motion, there can likely be a stretch at the capsular ligaments, causing a slight anterior tilting of the scapula. This forward tilt may enhance the extent of a backward reach.  Kinematics of GH Joint Shoulder External Rotation The convex humeral head simultaneously rolls posteriorly and slides anteriorly on concave glenoid fossa. Shoulder Internal Rotation The convex humeral head simultaneously rolls anteriorly and slides posteriorly on concave glenoid fossa. Kinematics of GH Joint 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle A posterior view of the joint opened up from behind, showing the clavicular facet on the acromion and the disc. 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Scapulothoracic Joint (Since it’s a functional joint, it doesn't have traditional ligaments. The stability comes mainly from the muscles surrounding it.) 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Sternoclavicular Joint  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Glenohumeral Joint 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Pectoralis Major Origin: medial 1/2 of the clavicle, manubrium & body of sternum, costal cartilages of ribs 2-6, sometimes from the rectus sheath of the upper abdominal wall Insertion: crest of the greater tubercle of the humerus Action: flexes and adducts the arm, medially rotates the arm Nerve: medial and lateral pectoral nerves (C5-T1)  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Pectoralis Minor Origin: external surfaces of ribs 3-5 Insertion: coracoid process of the scapula Action: draws the scapula forward, medially, and downward Nerve: medial pectoral nerve (C8, T1)  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Subclavius Origin: first rib and its cartilage Insertion: inferior surface of the clavicle Action: draws the clavicle (and hence the shoulder) down and forward Nerve: nerve to subclavius (C5)  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Trapezius Origin: medial third of the superior nuchal line, external occipital protuberance, ligamentum nuchae, spinous processes of vertebrae C7-T12 Insertion: lateral third of the clavicle, medial side of the acromion and the upper crest of the scapular spine, tubercle of the scapular spine Action: elevates and depresses the scapula (depending on which part of the muscle contracts); rotates the scapula superiorly; retracts scapula Nerve: motor: spinal accessory (XI), proprioception: C3-C4  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Latissimus Dorsi Origin: vertebral spines from T7 to the sacrum, posterior third of the iliac crest, lower 3 or 4 ribs, sometimes from the inferior angle of the scapula Insertion: floor of the intertubercular groove Action: extends the arm and rotates the arm medially Nerve: thoracodorsal nerve (C7,8) from the posterior cord of the brachial plexus  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Serratus Anterior Origin: outer surfaces of ribs 1-8 or 9 Insertion: medial border of the scapula on its costal (deep) surface Action: it draws the scapula forward; the inferior fibers rotate the scapula superiorly Nerve: long thoracic nerve (from ventral rami C5-C7)  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Levator Scapulae Origin: transverse processes of C1-C4 vertebrae Insertion: medial border of the scapula from the superior angle to the spine Action: elevates the scapula Nerve: dorsal scapular nerve (C5)  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Rhomboideus major Origin: spines of vertebrae T2-T5 Insertion: medial border of the scapula inferior to the spine of the scapula Action: retracts, elevates and rotates the scapula inferiorly Nerve: dorsal scapular nerve (C5)  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Rhomboideus minor Origin: inferior end of the ligamentum nuchae, spines of vertebrae C7 and T1 Insertion: medial border of the scapula at the root of the spine of the scapula Action: retracts, elevates and rotates the scapula inferiorly Nerve: dorsal scapular nerve (C5)  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Teres Major Origin: dorsal surface of the inferior angle of the scapula Insertion: crest of the lesser tubercle of the humerus Action: adducts the arm, medially rotates the arm, assists in arm extension Nerve: lower subscapular nerve (C5,6) from the posterior cord of the brachial plexus ROTATOR CUFF MUSCLES S - Supraspinatus I - Infraspinatus T - Teres Minor S - Subscapularis  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Rotator Cuff Muscles Is a group of muscles and their tendons that act to stabilize the shoulder. are important in shoulder movements and in maintaining glenohumeral joint (shoulder joint) stability. These muscles arise from the scapula and connect to the head of the humerus, forming a cuff at the shoulder joint. They hold the head of the humerus in the small and shallow glenoid fossa of the scapula.  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Supraspinatus Origin: supraspinous fossa Insertion: greater tubercle of the humerus (highest facet) Action: abducts the arm (initiates abduction) Nerve: suprascapular nerve (C5,6) from the superior trunk of the brachial plexus  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Infraspinatus Origin: infraspinatous fossa Insertion: greater tubercle of the humerus (middle facet) Action: laterally rotates the arm Nerve: suprascapular nerve  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Teres Minor Origin: upper 2/3 of the lateral border of the scapula Insertion: greater tubercle of the humerus (lowest facet) Action: laterally rotates the arm Nerve: axillary nerve (C5,6) from the posterior cord of the brachial plexus  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Subscapularis Origin: medial two-thirds of the costal surface of the scapula (subscapular fossa) Insertion: lesser tubercle of the humerus Action: medially rotates the arm; assists extention of the arm Nerve: upper and lower subscapular nerves (C5,6) 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle MUSCLES OF THE ARM 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Deltoid Muscles Anterior Deltoid Middle/Lateral Deltoid Posterior Deltoid  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Deltoid Origin: lateral one-third of the clavicle, acromion, the lower lip of the crest of the spine of the scapula. It has anterior fibers, posterior fibers and middle fibers. Insertion: deltoid tuberosity of the humerus Action: Anterior fibers - abducts arm, flex & medially rotate the arm posterior fibers - extend & laterally rotate the arm middle fiber - contribute maximum to abduction of arm. Nerve: axillary nerve (C5,6) from the posterior cord of the brachial plexus  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Coracobrachialis Origin: coracoid process of the scapula Insertion: medial side of the humerus at mid-shaft Action: flexes and adducts the arm Nerve: musculocutaneous nerve (C5,6)  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Biceps Brachii Origin: short head: tip of the coracoid process of the scapula; long head: supraglenoid tubercle of the scapula Insertion: tuberosity of the radius Action: flexes the forearm, flexes arm (long head), supinates Nerve: musculocutaneous nerve (C5,6)  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Biceps Brachii Long head and Short head insertion points Long head Short head  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Brachialis Origin: anterior surface of the lower one-half of the humerus and the associated intermuscular septa Insertion: coronoid process of the ulna Action: flexes the forearm Nerve: musculocutaneous nerve (C5,6)  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Brachioradialis Origin: upper two-thirds of the lateral supracondylar ridge of the humerus Insertion: lateral side of the base of the styloid process of the radius Action: flexes the elbow, assists in pronation & supination Nerve: radial nerve  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Triceps brachii Triceps has three heads of origin Origin: long head: infraglenoid tubercle of the scapula; lateral head: posterolateral humerus & lateral intermuscular septum; medial head: posteromedial surface of the inferior 1/2 of the humerus Insertion: olecranon process of the ulna Action: extends the forearm; the long head extends and adducts arm Nerve: radial nerve  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Triceps brachii  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Muscles of scapulothoracic region Anconeus Origin: lateral epicondyle of the humerus Insertion: lateral side of the olecranon and the upper one-fourth of the ulna Action: extends the forearm Nerve: radial nerve 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Innervation of the Muscles and Joints of the Shoulder Complex INTRODUCTION TO THE BRACHIAL PLEXUS major nerves supplying the upper limb originate from the brachial plexus. The brachial plexus is a network of nerves that comes from the spinal cord and controls muscle movements and sensation in the shoulder, arm and hand. Therefore, it provides innervation of the upper limb. The Brachial Plexus is formed by the ventral rami of lower four cervical nerves & the 1st thoracic nerve to give it a root value : of C5,6,7,8 &T1.  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Innervation of the Muscles and Joints of the Shoulder Complex INTRODUCTION TO THE BRACHIAL PLEXUS Majority of the muscles that comes from shoulder complex receive their motor innervation from two regions of the brachial plexus: (1) nerves that branch from the posterior cord, such as the axillary, subscapular, and thoracodorsal nerves. (2) nerves that branch from more proximal segments of the brachial plexus, such as the dorsal scapular, long thoracic, pectoral, and suprascapular nerves. An exception to this innervation scheme is the trapezius muscle, which is innervated primarily by cranial nerve XI, with lesser motor and sensory innervation from nerve roots of the upper cervical nerves. 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Trunks divide to form divisions Anterior Division (C5 & C6) Upper Trunk Posterior Division Anterior Division (C7) Middle Trunk Posterior Division Anterior Division (C8 & T1) Lower Trunk Posterior Division 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Easy to draw schematic diagram of the brachial plexus 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Axillary Nerve It is a branch of posterior cord of the brachial plexus. Root Value: C5,C6 Runs posterior to the neck of the humerus. Supplies Deltoid and teres minor. Runs over inferior half of deltoid.  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Musculocutaneous Nerve Branch of the lateral cord of the brachial plexus Anterior arm. Innervates arm flexors. Distal to elbow, becomes cutaneous – sensation on lateral forearm, anteriorly and posteriorly Muscles supplied: Coracobrachialis, Biceps brachii, Brachialis.  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Ulnar Nerve Branch of medial cord of brachial plexus. Descends along medial side of arm. Passes posterior to medial epicondyle = “funny bone”. Runs with ulnar artery in forearm. Innervates flexor carpi ulnaris and medial flexor digitorum profundus in forearm. Supplies intrinsic muscles of hand. Skin of medial 1/3 of hand anteriorly and posteriorly  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Median Nerve Branch of medial and lateral cords of brachial plexus. Travels with brachial artery in arm, with radial artery in forearm. Muscles of flexor compartment of forearm except flexor carpi ulnaris and medial flexor digitorum profundus. Through carpal tunnel to intrinsic muscles of hand. Skin of lateral 2/3 of hand on palm side and dorsum of fingers 2 and 3.  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Radial Nerve Largest branch of brachial plexus originating from posterior cord. Runs in the spiral groove on the back of the humerus supplying posterior compartment of arm. Curves anteriorly around lateral epicondyle, dividing into superficial and deep branch. Superficial branch to skin on dorsolateral surface of hand Deep branch (posterior interossoeus nerve) to extensor muscles of forearm.  3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Arm Summary Anterior compartment – Hand musculocutaneous except brachioradialis Median nerve – lateral muscle (radial nerve) 2 lumbricals, abductor Posterior compartment – and flexor pollicis brevis, radial nerve and opponens pollicis Forearm Anterior compartment – Ulnar nerve – palmar median except 1and 1/2 interossei, dorsal muscles which are ulnar interossei, medial 2 (flexor carpi ulnaris and lumbricals, adductor medial part of flexor pollicis, hypothenar digitorum profundus) muscles. Posterior compartment – radial nerve and its branches 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Dermatomes 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle 3.2 Ligaments, Summary of Nerve muscles with the Supply of the Shoulder nerve supply of the Complex shoulder girdle (Scapulothoracic Joint) 3.2 Ligaments, muscles with the Summary of Nerve Supply of the Shoulder Complex nerve supply of the shoulder girdle (Sternoclavicular Joint) 3.2 Ligaments, Summary of Nerve muscles with the Supply of the Shoulder nerve supply of the Complex shoulder girdle (Glenohumeral Joint) 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle AXILLA Axilla is a pyramidal space situated between the upper part of the arm and the chest wall. It is slightly oblique- the apex is upward and medially and the base is downward(floor). 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle Base/floor : skin Anterior wall : pectoralis major Posterior wall : - subscapularis (above) - teres major & latissimus dorsi (below) Medial wall : - upper four ribs and intercostal muscles - upper part of serratus anterior Lateral wall : - humerus - coracobrachialis, biceps brachii 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle 3.2 Ligaments, muscles with the nerve supply of the shoulder girdle  3.3 Kinesiology of shoulder girdle Scapulohumeral Rhythm refers to the coordinated movement between the scapula and the humerus during arm elevation. For every 2 degrees of glenohumeral movement, there is 1 degree of scapular movement. Importance: This rhythm is essential for full abduction and flexion of the shoulder, ensuring a smooth and coordinated motion while maintaining joint stability.  3.3 Kinesiology of shoulder girdle Open Kinematic Chain Movements of the Glenohumeral Joint In open kinematic chain (OKC) movements, the distal end of the limb (hand) is free to move, and the proximal segments remain fixed. The movements in the glenohumeral joint during open- chain activities are more isolated and primarily involve movement of the shoulder without direct load bearing.  3.3 Kinesiology of shoulder girdle Examples: Throwing a ball: The hand moves freely through the air while the shoulder joint is actively moving in flexion, abduction, and rotation. Lifting a weight with your arm: During a bicep curl, the shoulder stays relatively stable while the elbow and hand move independently. Reaching overhead: The distal part (hand) moves freely while the shoulder performs flexion and abduction.  3.3 Kinesiology of shoulder girdle Closed Kinematic Chain Movements of the Glenohumeral Joint In closed kinematic chain (CKC) movements, the distal end of the limb (hand) is fixed or in contact with a surface, and the proximal joints (shoulder) move in response. This involves co-contraction of multiple muscles and more stability of the glenohumeral joint since the movement occurs through both the shoulder and the rest of the body.  3.3 Kinesiology of shoulder girdle Examples: Push-up: The hands are in contact with the ground, and the movement involves the shoulder joint performing flexion/extension as well as stabilization of the body. Pull-up: The hands are fixed on a bar, and the shoulder joint performs adduction and extension, along with stabilizing actions to pull the body upwards. Plank hold: The hands remain in a static position while the shoulder joint works to stabilize the body in a closed chain position.  3.3 Kinesiology of shoulder girdle Kinesiology of Common Functional Activities Reaching Overhead Involves a combination of flexion, abduction, and external rotation. Scapular upward rotation is essential for full overhead movement. Pushing/Pulling Movements Require coordination between the deltoid, pectoralis major, latissimus dorsi, and rotator cuff muscles to stabilize the shoulder. Throwing and Lifting Involves dynamic shoulder motion, including rapid internal and external rotation. The scapulothoracic joint plays a key role in stabilizing the shoulder during these high- speed movements.  References Moore, K. L., Dalley, A. F., & Agur, A. M. (2013). Clinically Oriented Anatomy (7th ed.). Lippincott Williams & Wilkins. Neumann, D. A. (2016). Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation (3rd ed.). Elsevier. Magee, D. J. (2014). Orthopedic Physical Assessment (6th ed.). Saunders. Kisner, C., & Colby, L. A. (2017). Therapeutic Exercise: Foundations and Techniques (7th ed.). F.A. Davis. THANK YOU