Shoulder Anatomy Quiz

• The appendicular skeleton includes the pectoral girdle and upper limbs.

Pectoral Girdle

• Composed of 4 bones: 2 clavicles and 2 scapulae
• The pectoral girdle connects the upper limbs to the axial skeleton
• Clavicles connect to the scapula and sternum via ligaments.
• Scapula articulates with clavicle and humerus and is positioned over the rib cage.

Clavicle

• The clavicle has an acromial end and a sternal end.
• The acromial end is rounder and flattened, articulating with the acromion process of the scapula at the acromioclavicular joint
• The sternal end is flatter and thicker, articulating with the sternum at the sternoclavicular joint.

Scapula

• Features include the spine, acromion, supraspinous fossa, infraspinous fossa, subscapular fossa, glenoid cavity, coracoid process, medial border, and lateral border.
• The spine (scapular spine) is a bony ridge palpable through the skin, serving as a muscle attachment site for scapular movement.
• The acromion (acromion process) is a platelike extension of the spine that articulates with the clavicle, also palpable on the shoulder.
• Supraspinous fossa is a depression above the spine.
• Infraspinous fossa is a depression below the spine.
• Subscapular fossa is a depression under the scapula that faces the ribs.
• Glenoid fossa (glenoid cavity) is a hyaline cartilage-covered depression that articulates with the humerus head.
• Coracoid process is a beak-shaped bone piece for muscle attachment to move the scapula.
• The medial border is the scapula's edge that faces the spine.
• The lateral border is the edge of the scapula that faces the humerus.

Upper Limbs

• Humerus, radius, ulna, carpals, metacarpals, and phalanges are the bones

Humerus

• Features include the head, greater tubercle, lesser tubercle, intertubercular sulcus, deltoid tuberosity, capitulum, radial fossa, trochlea, coronoid fossa, olecranon fossa, medial epicondyle, and lateral epicondyle.
• The headis round, hyaline cartilage-covered end that articulates with the glenoid fossa.
• The greater tubercle is a large, rough area next to the head where muscles attach
• The lesser tubercle is a small, rough area next to the head where muscles attach
• The intertubercular groove (intertubercular sulcus) is a narrow depression running down the shaft that holds a shoulder ligament.
• The deltoid tuberosity is a rough area of the shaft where the deltoid muscle attaches
• The medial epicondyle is where forearm flexor muscles attach and can be palpated on the inside of the elbow
• The lateral epicondyle is where forearm extensor muscles attach and can be palpated on the outside of the elbow
• The capitulumis a round, hyaline-cartilage covered articulation for the radius bone
• The radial fossa is a shallow depression above the capitulum receiving the radius head when the elbow is flexed
• The trochlea is a hyaline cartilage-covered V-shaped depression that articulates with the ulna
• The coronoid fossa is a shallow depression above the trochlea that receives the ulna's coronoid process when the elbow is flexed
• The olecranon fossa receives the olecranon of the ulna allowing the elbow to extend

Radius

• Features include the head, neck, radial tuberosity, ulnar notch, and styloid process.
• The head is the round, hyaline cartilage-covered end that articulates with the humerus capitulum
• The neckis the skinny part of the radius below the head
• The radial tuberosity is a raised, rough area just below the neck for biceps brachii muscle insertion that flexes the elbow joint
• The ulnar notch is a small depression where the ulna head articulates with the radius
• The styloid process is the small, pointed tip of the radius at the wrist.

Ulna

• Features include the olecranon, trochlear notch, radial notch, coronoid process, and styloid process.
• The olecranon (olecranon process) is a heavy bone piece commonly referred to as "the elbow"
• The trochlear notch is a U-shaped depression that wraps around the humerus trochlea.
• The coronoid process is the raised lip of the trochlear notch for brachialis muscle insertion that flexes the elbow joint
• The radial notch is a shallow depression that the radius head articulates with during pronation and supination of the forearm.
• The styloid process is the small, pointed tip of the ulna at the wrist.

Interosseous Membrane

• The interosseous Membrane is a strong, thin, flexible connective tissue sheet that binds the radius and ulna, allowing radius movement for pronation and supination

Carpal, Metacarpals, Phalanges

• Carpals are the wrist bones (names not tested).
• Metacarpals are the hand bones.
• Phalanges are the finger bones.

Muscles of the Pectoral Girdle and Upper Extremity

• Deltoid: abducts humerus at shoulder; originates at the acromion and spine of scapula; inserts at the deltoid tuberosity of humerus
• Pectoralis major: adducts and flexes humerus at the shoulder; originates at the sternum and clavicle; inserts at the intertubercular groove of humerus
• Latissimus dorsi: adducts and extends humerus at shoulder; originates at the spine (lumbar); inserts at the intertubercular groove of humerus
• Teres major: adducts humerus at the shoulder; originates at the scapula; inserts at the intertubercular groove of humerus
• Coracobrachialis: adducts humerus at the shoulder; originates at the coracoid process of the scapula; inserts at the shaft of the humerus
• Trapezius: elevates, depresses, and retracts scapula; originates at the spine (cervical and thoracic); inserts at the spine of the scapula
• Pectoralis minor: protracts and depresses scapula; originates at the ribs; inserts at the coracoid process of scapula
• Serratus anterior: protracts scapula; originates at the ribs; inserts at the medial border of scapula
• Rhomboid major: retracts scapula; originates at the spine; inserts at the medial border of scapula
• Rhomboid minor: retracts scapula; originates at the spine; inserts at the medial border of scapula

Rotator Cuff Muscles (SITS)

• Supraspinatus, infraspinatus, teres minor, and subscapularis are all part of the rotator cuff muscles and do circumduction of humerus at shoulder
• Supraspinatus: originates at the supraspinous fossa of scapula; inserts at the greater tubercle of humerus
• Infraspinatus: originates at the infraspinous fossa of scapula; inserts at the greater tubercle of humerus
• Teres minor: originates at the scapula; inserts at the greater tubercle of humerus
• Subscapularis: originates at the subscapular fossa of scapula; inserts at the lesser tubercle of humerus

Muscles Acting on Forearm at Elbow

• Biceps brachii: flexes forearm at the elbow and supinates forearm; originates at the scapula; inserts at the radial tuberosity of the radius.
• Brachialis: flexes forearm at the elbow; originates at the shaft of humerus; inserts at the coronoid process of ulna
• Brachioradialis: flexes forearm at the elbow; originates at the humerus; inserts at the styloid process of the radius
• Triceps brachii (long head): extends forearm at the elbow; originates at the scapula and humerus; inserts at the olecranon process of ulna.
• Triceps brachii (lateral head): extends forearm at the elbow; originates at the humerus; inserts at the olecranon process of ulna.
• Triceps brachii (medial head): extends forearm at the elbow; origin: humerus; insertion: olecranon process of ulna.
• Anconeus: extends forearm at the elbow; originates at the lateral epicondyle of humerus; inserts at the olecranon process of ulna

Forearm Muscles (Anterior)

• The cubital fossa is a gross anatomical landmark bounded by brachioradialis and pronator teres
• Pronator teres: pronates forearm; originates at the medial epicondyle of humerus; inserts at the radius
• Flexor carpi radialis: flexes wrist, radial deviation of hand; originates at the medial epicondyle of humerus; inserts at the wrist
• Palmaris longus: flexes wrist; originates at the medial epicondyle of humerus; inserts at the connective tissue of wrist and palm.
• Flexor carpi ulnaris: flexes wrist, ulnar deviation of hand; originates at the medial epicondyle of humerus; inserts at the wrist
• Flexor digitorum superficialis: flexes fingers; originates at the medial epicondyle of humerus; inserts at phalanges 2-5
• Flexor digitorum profundus: flexes fingers; originates at the ulna; inserts at phalanges 2-5
• Flexor pollicis longus: flexes thumb; originates at the radius; inserts at the base of the thumb
• Pronator quadratus: pronates forearm; originates at the ulna; inserts at the radius
• The flexor retinaculum is a connective tissue sheath that covers the carpal tunnel

Forearm Muscles (Posterior)

• Extensor carpi radialis longus: extends wrist; radial deviation of hand; originates at the humerus; inserts at the wrist
• Extensor carpi radialis brevis: extends wrist; radial deviation of hand; originates at the lateral epicondyle of humerus; inserts at the wrist
• Extensor digitorum: extends fingers; originates at the lateral epicondyle of humerus; inserts at phalanges 2-5
• Extensor digiti minimi: extends little finger; originates at the lateral epicondyle of humerus; inserts at phalanx #5
• Extensor carpi ulnaris: extends at wrist, ulnar deviation of hand; originates at the lateral epicondyle of humerus; inserts at the wrist
• Supinator: supinates forearm; originates at the ulna; inserts at the radius
• Abductor pollicis longus: abducts thumb; originates at the radius and ulna; inserts at the base of the thumb
• Extensor pollicis brevis: extends thumb; originates at the radius; inserts at the base of the thumb
• Extensor pollicis longus: extends thumb; originates at the ulna; inserts at the base of thumb
• Extensor indicis (also spelled extensor indices): extends index finger; originates at the ulna; inserts at the index finger
• Extensor retinaculum: connective tissue sheath that holds down the extensor tendons

Intrinsic Muscles of the Hand

• Thenar group (4 muscles): circumducts thumb
• Abductor digiti minimi: abducts little finger

Histology for Practical 2

Integument

• Epidermis: identify the specific tissue that comprises the epidermis; identify strata (layers) and structures located here. Structures: stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale

Dermis

• Dermis: identify the tissue primarily comprising the dermis; identify layers and structures located here. Structures: dermal papillae, papillary layer, and reticular layer.

Hypodermis

• Hypodermis: identify the type of tissue comprising the hypodermis; identify components. Structures: adipose tissue

Compact Bone

• Structures: osteon (Haversian system), central canal (Haversian canal), lacunae (osteocytes contained inside), canaliculi (canaliculus = singular), concentric lamellae (lamella = singular), and perforating canal (Volkmann's canal).

Definitions of Structures

• Acromion: comes from the Greek "akron," peak + "omos," shoulder.
• Capitulum: smooth, rounded eminence (capitulum of humerus).
• Coracoid: resemblance to crow's beak (coracoid process of the scapula).
• Coronoid: Corono – crown (coronoid process of the mandible, coronoid process of the ulna).
• Epicondyle: epi – upon; projection superior to a condyle (medial epicondyle of the femur).
• Facet: smooth, slightly concave or convex articular surface (articular facets of vertebrae).
• Fossa: shallow, broad, or elongated basin (mandibular fossa).
• Glenoid: from Greek: gléne, "socket" (glenoid cavity).
• Head: prominent expanded end of a bone (head of rib, head of femur, head of humerus).
• Olecranon: large, thick, curved eminence (olecranon of the humerus).
• Phalanx: Greek word from “phalangos,” meaning finger (phalanges of the fingers and toes).
• Pollicis: Latin meaning of “Pollex” is thumb (flexor and extensor pollicis longus, abductor pollicis longus).
• Rhomboid: parallelogram in which adjacent sides are of unequal lengths and angles are oblique (rhomboid major and rhomboid minor).
• Serratus: serrated refers to a finely notched edge (serratus anterior).
• Spine: sharp, slender, or narrow process (spine of the scapula).
• Styloid: Stylus - ancient Greeks/Romans used these to write on wax tablets.
• Sulcus: a groove for tendon, nerve, or blood vessel (intertubercular sulcus of humerus).
• Trochlea: Latin for pulley (trochlea of humerus).
• Tubercle: small, rounded process (greater and lesser tubercles of humerus).
• Tuberosity: rough elevated surface (tibial tuberosity).

Important Terms and Definitions

• Anatomical position: starting position (descriptions relate to anatomical position); toes forward, feet apart, arms at sides, palms forward.

Movement

• Flexion: decrease joint angle.
• Extension: increase joint angle.
• Abduction: moving a body part away from the body midline.
• Adduction: returning a body part toward the body midline.
• Medial Rotation: turning a body part on axis toward midline (internal rotation).
• Lateral Rotation: turning a body part on axis away from midline (external rotation).
• Lateral flexion: bending body sideways.
• Elevation: lifting a body part (in frontal plane).
• Depression: lowering a body part (in frontal plane).
• Protraction: sliding a body part forward (in horizontal plane).
• Retraction: sliding a body part backward (in horizontal plane).
• Supination: turn palms toward anatomical position, uncross radius & ulna.
• Pronation: turn palms to back; cross radius & ulna.
• Dorsiflexion: bending ankle so that the toes are raised.
• Plantar Flexion: extending ankle joint so toes point downwards.
• Circumduction: combination of movements that create a complete circle.

Direction

• Ventral/Anterior: toward the belly/toward the front.
• Dorsal/Posterior: toward the back/toward the rear.
• Distal: away from, farther from the origin.
• Proximal: near, closer to the origin.
• Superior: above, over.
• Inferior: below, under.
• Lateral: toward the side, away from the mid-line.
• Medial: toward the midline, middle, away from the side.
• Rostral: toward the front, toward the nose.
• Caudal: toward the back, toward the tail.
• Superficial: closer to the surface, more external.
• Deep: further from the surface, more internal.

Test your knowledge of shoulder anatomy! Questions cover muscles involved in humerus abduction, scapular movement, and the impact of injuries in the shoulder region. Challenge yourself with questions on muscle origins, insertions, and affected movements.