Humerus Flashcards
First thing to evolve in earliest fish?
upper arm
- all axial “skeleton” at this point
The tetrapod arm evolved from ________ _____ of lobe-finned fish
pectoral fins
The evolution of limbs was a precursor to animals becoming terrestrial
True
Pectoral fins evolved in early fish to aid in ___________
locomotion
- steering and stabilization
We recently got our first look at a complete pectoral fin from a middle Devonian lobe-finned fish
- tetrapod-like fish with a well-preserved pectoral fin
(genus Elpistostege)
3 bones that compose the arm
1.) Humerus
- proximally
2.) Ulna
- distal and medial
3.) Radius
- distal and lateral
Brachial
related to the arm (especially to the upper arm)
- humerus
Antebrachial
related to the forearm
- ulna and radius
Joints of the humerus
- glenohumeral joint
- humeroulnar joint
- humeroradial joint
Glenohumeral joint
the humeral head articulates with the glenoid fossa (scapula)
Humeroulnar joint
the trochlea (humerus) articulates with ulna
Humeroradial joint
the capitulum (humerus) articulates with the radius
Tubercle
a rugose eminence, often the site of tendon or ligament attachment
Epicondyle
a non-articular projection adjacent to a condyle
Trochlea
a spool-shaped structure with a groove in the middle and raised ridges on either side
Capitulum
a spherical structure
The anatomical neck is the attachment region of the ________ joint capsule
glenohumeral
Under the glenohumeral ligament is the capsule, which is also called what?
Bursa
Muscles of the rotator cuff
1.) Supraspinatus muscle
2.) Infraspinatus muscle
3.) Subscapularis muscle
4.) Teres minor muscle
- anchors arm to body
The subscapularis muscle inserts on the_________
lesser tubercle
The supraspinatus, infraspinatus, and teres minor muscle inserts on the________
greater tubercle
Soft tissue attachment is so strong that bone often breaks before the joint separates
breaks at the surgical neck
The greater tubercle is _______ to the lesser tubercle
lateral
Crest of the lesser tubercle (medial part of intertubercular groove) is the insertion site for what muscles?
- latissimus dorsi
- teres major
The most conspicuous structure on the shaft of the humerus?
Deltoid tuberosity
Because the deltoid has such a broad origin, it can produce many different movements
True
The shaft changes cross-sectional shape along its length
Goes from more circular (proximal) to more triangular (distal)
The shaft is divided into three surfaces
1.) Posterior surface
2.) Anteromedial surface
3.) Anterolateral surface
Between the anatomical neck and the deltoid tuberosity, you will find the crest for________ on the posterior surface
triceps brachii
The ___________ is located on just inferior to the deltoid tuberosity on the posterior surface
Radial sulcus
- spiral groove
The radial sulcus spirals from_____________ to _____________
superoposterior to inferolateral
The primary nutrient foramen is about at the deltoid tuberosity level, typically on the _________ surface
anteromedial
The nutrient foramen opens_______
proximally
The ________ nerve wraps around the posterior surface of the medial epicondyle
Ulnar nerve
The nerve that goes numb when you “hit your funny bone”
ulnar nerve
Medial epicondyle provides attachment to what?
- wrist flexors
- Pronator teres
Pronator teres
pulls radius in to do pronation
Lateral epicondyle provides attachment to what?
supinator muscle
