Overview
This lecture covers the anatomical terminology, regions, bones, and important landmarks of the elbow and forearm, focusing on their relevance for movement and muscle attachment.
Elbow and Regional Terminology
- The technical name for the elbow region is "cubital."
- The front of the elbow is the "antecubital region" (site for blood draws).
- The back of the elbow features the "olecranon process" (olecranon region).
- The upper arm (shoulder to elbow) is the "brachial" region; forearm (elbow to wrist) is "antebrachial."
- Arm muscle names often include "brachii" for location clarity.
Movements of the Elbow and Forearm
- In anatomical position, palms face forward; in relaxed/neutral, palms face each other.
- "Supination" is palm up; "pronation" is palm down; "mid-position" or "neutral" is halfway.
- Flexion: decreases joint angle (e.g., bending the elbow).
- Extension: increases joint angle (e.g., straightening the elbow).
Elbow Muscles Overview
- Biceps brachii: two-headed muscle, main elbow flexor, also acts at the shoulder.
- Brachialis: lies under biceps, strongest elbow flexor, attaches to ulna.
- Biceps is strongest in supinated position; brachialis is strong in all positions.
- Muscles that move the forearm must attach to the radius or ulna.
Bones and Landmarks of the Elbow Region
Scapula
- Borders: medial (vertebral), lateral (axillary), and superior.
- Angles: superior, inferior, lateral (contains glenoid fossa for humerus articulation).
- Supraglenoid tubercle (biceps origin) and infraglenoid tubercle (triceps origin).
- Spine of scapula separates supraspinous and infraspinous fossae.
- Acromion is the highest point; root of spine connects to medial border.
Humerus
- Proximal end: head, greater and lesser tubercles, intertubercular (bicipital) groove.
- Deltoid tuberosity (attachment for deltoid muscles).
- Distal end: medial and lateral condyles; medial = trochlea, lateral = capitulum.
- Epicondyles and supracondylar ridges for muscle attachment.
- Fossae: coronoid (anterior), olecranon (posterior), radial (anterior).
Forearm Bones
Radius
- Proximal end: head, radial tuberosity.
- Interosseous border (between radius and ulna).
- Distal end: styloid process, dorsal (Lister's) tubercle, ulnar notch.
Ulna
- Proximal end: olecranon process (posterior), coronoid process (anterior), trochlear notch.
- Ulnar tuberosity (brachialis attachment), radial notch.
- Interosseous border; supinator crest.
- Distal end: head, styloid process.
- Both radius and ulna have styloid processes at the distal end.
Key Terms & Definitions
- Supination — Turning the palm up.
- Pronation — Turning the palm down.
- Flexion — Decreasing the angle at a joint.
- Extension — Increasing the angle at a joint.
- Tubercle/Tuberosity — Bony bump for muscle/ligament attachment.
- Condyle — Rounded joint surface at bone end.
- Epicondyle — Bump on a condyle.
- Fossa — Shallow depression in bone.
- Process — Bone projection or outgrowth.
Action Items / Next Steps
- Review bone landmarks and practice identifying them on yourself.
- Study muscle attachments and their specific functions at the elbow.
- Prepare for next lecture on elbow muscles and movements.