Superficial Back and Shoulder Muscles PDF

SUPERFICIAL MUSCLES of BACK & SHOULDER REGION Muscles of Back Superficial group→ upper limb Intermediate group→ respiratory functions Deep group → vertebral column & head Superficial Muscles of Back Superficial Back Muscles Trapezius muscle Latissimus dorsi muscle Levator scapulae Rhomboid minor Rho...

SUPERFICIAL MUSCLES of BACK & SHOULDER REGION Muscles of Back Superficial group→ upper limb Intermediate group→ respiratory functions Deep group → vertebral column & head Superficial Muscles of Back Superficial Back Muscles Trapezius muscle Latissimus dorsi muscle Levator scapulae Rhomboid minor Rhomboid major Trapezius Muscle Origin of Trapezius superior nuchae line ext occipital protuberence Lig nuchae C7 vertebra (ver tebra prominence) spinous process of all thoracal ver tebra supraspinal lig Insertion of Trapezius Superior part (descending fibers)→ lateral 1/3 of the clavicle Middle part (transverse fibers)→acromion & spine of scapula Inferior part (ascending fibers)→ trigonum of the scapula Function of the Trapezius Superior part (descending fibers): elevates the clavicle Middle part (transverse fibers): retract the scapula (pull it posteriorly) Inferior part (ascending fibers): depresses the scapula Trapezius - Assists in suspending the upper limb -Descending (superior) fibers elevate the scapula (e.g., when squaring the shoulders). -Middle fibers retract the scapula (i.e., pull it posteriorly). -Ascending (inferior) fibers depress the scapula and lower the shoulder. Innervation of the Trapezius Accessory nerve (spinal part)[XI th cranial nerve] Trapezius Latissimus dorsi -Pelvic origin -Primary adductor-shoulder -Climbing -Widest muscle LATISSIMUS DORSI O: T7 inferior 6 th v lumbar v supraspinal lig iliac crest inferior 3 or 4 ribs lower thoracal & lumbar regions L5 clinically oriented ANATOMY. Keith L. Moore, Arthur F. Dalley Insertion of the Latissımus dorsi floor of the intertubercular groove Crest of lesser tubercle Function of LATISSIMUS DORSI sagittal plane: adduct the arm vertical plane: medial rotation of arm coronal plane: extent the arm M. Latissimus Dorsi teres major powerfull adductor of arm inspiration & expiration main climbing muscle – (sternocostal part of pectoralis major, teres major and posterior part of deltoid) LEVATOR SCAPULAE O:transverse procc of C1-C4 I: near the superior angle innervation: Dorsal Scapular Nerve Function of the LEVATOR SCAPULA with the rhomboids and pectoralis minor→ Acting bilaterally Acting unilaterally RHOMBOID MINOR & MAJOR C7 T1 T2 T5 Dorsal scapular nerve Levator scapulae, Rhomboid major and minor: Retract and rotate the scapula, depressing its glenoid cavity Synergist & Antogonist Muscles The muscles rotate the scapula, depressing the glenoid cavity Levator scapula m Rhomboid major m The muscles rotate the scapula, elevating the glenoid cavity Inferior part of serratus anterior muscle Trapezius (superior & inferior parts) HYPERABDUCTI ON Rhomboid minor m Pectoralis minor m Triangle of Auscultation floor: rhomboid major, 6.7. ribs Triangle of Auscultation Inferior Lumbar Trigone (Petit’s Triangle ) Floor: internal abdominal oblique retroperitoneal structures may be herniated Scapulohumeral (Intrinsic Shoulder) Muscles Deltoid muscle Subscapular muscle Supraspinatus muscle Infraspinatus muscle Teres major muscle Teres minor muscle Shoulder Region Muscles Deltoid Clavicular part (ant part): Acromial part (middle part): Spinal part (posterior part) Deltoid anterior part (clavicular part) flexion & medial rotation of arm posterior part (spinal part) lateral rotation of arm and extends the arm middle part (acromial part) Deltoid Abductor of the arm Axillary nerve Apolette sign in lesions due to atrophy Axillary nerve Paralysis of axillary nerve Teres major insertion: crest of lesser tubercle innervation: Lower subscapular n Adduct-medially rotate & extend the arm Teres major Similar to Latissimus dorsi in function Lower subscapular nerve Rotator cuff muscles SIT+S Supraspinatus Infraspinatus teres minor Subscapularis Stabilize the shoulder joint Keep the head of humerus inside the glenoid cavity Rotator cuff muscles SIT+S Supraspinatus Infraspinatus teres minor GREATER TUBERCLE Subscapularis LESSER TUBERCLE Supraspinatus muscle -Starts the arm abduction (Assists deltoid) -Has no rotation function -Inserts to the tip of greater tubercle Innervated by suprascapular nerve Infraspinatus Suprascapular nerve Teres minor Axillary nerve Function External rotation of arm Suprascapular Nerve Teres minor Axillary nerve Subscapularis muscle Function: Internal rotation and adduction of arm (Only rotator cuff with internal rotation Innervation: Subscapular nerve Subscapularis muscle Only rotator cuff muscle which inserts to lesser tubercle of humerus Upper subscapular nerve Abduction of Arm 0-15 degrees Abduction 15-90 degrees Hyperabduction Deltoid (acromial Deltoid (acromial Serratus anterior part) part) (inferior part), Supraspinatus Trapezius (superior & inferior parts) Rotator Cuff Injuries MUSCLES OF THE ARM-POSTERIOR REGION Triceps Brachii Muscle radial n Anconeus O: Lateral epicondyle of humerus I: olecranon and superior part of posterior surface ulna Assists the triceps in extending forearm, tenses the capsule of the elbow joint Spaces of the Shoulder Region Three important spaces of the shoulder that are bordered by the triceps include: - Quadrangular space - Triangular space - Triangular interval Spaces of the Shoulder Region Quadrangular Space Borders: - Medial: long head of triceps - Lateral: humeral shaft - Superior: teres minor - Inferior: teres major Contents: - Axillary nerve - Posterior humeral circumflex artery Triangular Space Borders: - inferior: teres major - lateral: long head of triceps - superior: lower border of teres minor Contents: - scapular circumflex artery Triangular Interval Borders: - superior: teres major - lateral: lateral head of the triceps or the humerus - medial: long head of the triceps Contents: - profunda brachii artery - radial nerve Triangular interval Profunda brachii artery Movements of the scapula Protrusion Serratus ant Pectoralis minor Retraction Rhboid major Rhb minor Elevation Levator scapula Trapezius (Upper p) Depression Trapezius (lower) Pectoralis minor Elevation of Glenoid cavity Serratus ant trapezius Depression of Glenoid cavity Levator sc Rhb Trapezius (middle p) Pect minor