Muscles Flashcards
(115 cards)
Pectoralis major
Origins:
Clavicular head- anterior surface of the medial clavicle
Sternocostal head- anterior surface of the sternum, superior six costal cartilages, aponeurosis of the external oblique muscle
Attachments:
Distal attachment of both heads is into the intertubercular sulcus of the humerus
Innervation:
Lateral and medial pectoral nerves
Function:
Adducts upper limb
Medially rotates upper limb
Clavicular head acts individually to flex the upper limb
Pectoralis minor
Origin:
3rd-5th ribs
Insertion:
Coracoid process of scapula
Function:
Stabilises scapula by drawing it anteroinferiorly against the thoracic wall
Innervation:
Medial pectoral nerve
Serratus anterior
Origin:
Lateral aspects of ribs 1-8
Attachment:
Costal surface of the medial border of the scapula
Function:
Rotates the scapula
Abduction above 90 degrees
Holds scapula against the rib cage
Innervation:
Long thoracic nerve
Subclavius
Origin:
Junction of 1st rib and its costal cartilage
Insertion:
Inferior surface of the middle third of the clavicle
Function:
Anchors and depresses clavicle
Provides some protection of neurovascular structures beneath it
Innervation:
Nerve to subclavius
What are the muscles of the pectoral region?
Pectoralis major
Pectoralis minor
Serratus anterior
Subclavius
Deltoid
Origin:
Scapula
Clavicle
Attachment:
Deltoid tuberosity on lateral surface of humerus
Innervation:
Axillary nerve
Actions:
Anterior fibres flex the arm at the shoulder
Posterior fibres extend the arm at the shoulder
Middle fibres are the major abductor of the arm, 15-90 degrees
Teres major
Origin:
Posterior surface of inferior angle of scapula
Attachment:
Intertubercular groove of humerus
Innervation:
Lower subscapular nerve
Actions:
Adducts at the shoulder
Medially rotates shoulder
Supraspinatus
Origin:
Supraspinous fossa of scapula
Attachment:
Greater tubercle of humerus
Innervation:
Suprascapular nerve
Actions:
Abducts the arm 0-15 degrees
Assists deltoid for 15-90 degrees
Infraspinatus
Origin:
Infraspinous fossa of scapula
Attachment:
Greater tubercle of humerus
Innervation:
Suprascapular nerve
Actions:
Laterally rotates arm
Subscapularis
Origin:
Subscapular fossa on costal surface of scapula
Attachment:
Lesser tubercle of humerus
Innervation:
Upper and lower subscapular nerves
Actions:
Medially rotates arm
Teres minor
Origin:
Posterior surface of scapula adjacent to its lateral border
Attachment:
Greater tubercle of humerus
Innervation:
Axillary nerve
Actions:
Laterally rotates the arm
What are the intrinsic muscles of the shoulder?
Deltoid Teres major Supraspinatus Infraspinatus Subscapularis Teres minor
What are the rotator cuff muscles?
Supraspinatus
Infraspinatus
Subscapularis
Teres minor
Trapezius
Origins:
Skull, nuchal ligament (ligament on neck) and spinous processes of C7-C112
Attachments:
Clavicle
Acromion
Scapula spine
Innervation:
Motor innervation- accessory nerve
Sensory innervation- C3 and C4 spinal nerves
Actions:
Upper fibres elevate the scapula and rotate it during abduction of the arm
Middle fibres retract the scapula
Lower fibres pull the scapula inferiorly
Latissimus Dorsi
Origins: Spinous processes of T6-T12 Iliac crest Thoracolumbar fascia Inferior three ribs
Attachment:
Fibres converge into a tendon that attaches to the intertubercular sulcus of the humerus
Innervation:
Thoracodorsal nerve
Actions:
Extension of upper limb
Adduction of upper limb
Medial rotation of upper limb
What are the superficial extrinsic muscles of the shoulder region?
Trapezius
Latissimus dorsi
Levator scapulae
Origin:
Transverse processes of C1-C4 vertebrae
Attachment:
Medial border of the scapula
Innervation:
Dorsal scapular nerve
Actions:
Elevates the scapula
Rhomboid major
Origin:
Spinous processes of T2-T5 vertebrae
Attachment:
Medial border of scapula between scapula spine and inferior angle
Innervation:
Dorsal scapula nerve
Actions:
Retracts and rotates the scapula
Rhomboid minor
Origin:
Spinous processes of C7-T1 vertebrae
Attachment:
Medial border of the scapula at the level of the spine of scapula
Innervation:
Dorsal scapula nerve
Actions:
Retracts and rotates the scapula
What are the deep extrinsic muscles of the shoulder region?
Levator scapulae
Rhomboid minor
Rhomboid major
Biceps brachii
Origin:
Long head originates from supraglenoid tubercle of scapula
Short head originates from coracoid process of scapula
Insertions:
Both heads insert dismally into the radial tuberosity and the fascia of the forearm via the bicipital aponeurosis
Innervation:
Musculocutaneous nerve
Coracobrachialis
Origin:
Coracoid process of the scapula
Attachment:
Medial side of the humeral shaft at the level of the deltoid tuberosity
Function:
Flexion of the arm at the shoulder, weak adduction
Innervation:
Musculocutaneous nerve
Brachialis
Origin:
Medial and lateral surfaces of the humeral shaft
Insertion:
Ulna tuberosity distal to the elbow joint
Function:
Flexion at the elbow
Innervation:
Musculocutaneous nerve with contributions from the radial nerve
Triceps brachii
Origin:
Long head originates from the infra glenoid tubercle
Lateral head originates from the humerus superior to the radial groove
Medial head originates from the humerus inferior to the radial groove
Attachment:
Heads converge onto one tendon and insert at the olecranon of the ulna
Function:
Extension of the arm at the elbow
Innervation:
Radial nerve