brachium: humerus

humerus

largest and longest bone of the upper extremity

head

bulbous proximal end, fits into glenoid cavity of scapula

anatomical neck

constricted region located inferolateral to the head

large projection on the lateral edge of the epiphysis of the humerus forming the lateral margin of the shoulder, site for muscles

greater tubercle

lies on the anterior and medial surface of the epiphysis, marking the insertion point of the subscapularis muscle

lesser tubercle

intertubercular groove

separates the greater and lesser tubercles; guides a tendon of the brachii muscle to its attachment point

surgical neck

narrowed region located distal to the tubercles; most frequently fractured part of the humerus

deltoid tuberosity

elevated surface that runs along the lateral border of the shaft, extending more than halfway down its length; attachment site for the deltoid muscle

radial groove

runs along the posterior margin of the deltoid tuberosity; guides radial nerve of upper extremity

articular condyle

dominates the distal, inferior surface of the humerus; a low ridge that divides the condyle into two distinct articular regions

articular condyles consist of the

trochlea and the capitulum

trochlea

medial condyle, spool shaped, articulates with the ulna

capitulum

lateral condyle, rounded region, articulates with the radius

medial and lateral EPIcondyles

attachment sites for forearm muscles

medial and lateral SUPRAcondylar ridges

attachment sites for the medial head of triceps and the brachioradialis muscles, respectively

olecranon fossa

posterior, articulates with olecranon process of ulna

coroNOID fossa

anterior, accepts projections, along with olecranon fossa, from the surface of the ulna as the elbow approaches full flexion or extension

radial fossa

anterior, shallow depression superior to the capitulum, accommodates a small part of the radial head as the forearm approaches the humerus