Summary of Appendicular Skeleton and Upper Limb Anatomy

Appendicular Skeleton & Upper Limb Anatomy Guide for Students

Summary Knowledge test Flashcards Podcast Mindmap

Introduction

The appendicular skeleton includes the bones that support the limbs and attach them to the axial skeleton. It is essential for movement, stability, and many daily activities like lifting, walking and grasping objects.

Definition: The appendicular skeleton is the part of the skeleton that comprises the pectoral girdle, upper limbs, pelvic girdle and lower limbs, and it connects the limbs to the axial skeleton.

Overview of the Appendicular Skeleton

The appendicular skeleton can be divided into two large groups:

Pectoral girdle and upper limbs
Pelvic girdle and lower limbs

These girdles act like belts that join the limbs to the axial skeleton and provide attachment points for muscles that control limb movement.

Pectoral Girdle

The pectoral girdle (shoulder region) consists of two bones on each side:

Scapula (shoulder blade) — large, flat, triangular bone on the back
Clavicle (collarbone) — S-shaped bone at the front

Scapula (shoulder blade)

Large, flat, triangular bone with a prominent ridge (the spine of the scapula) for muscle attachment.
Slides over the back of the ribs rather than being firmly attached to the axial skeleton.
Has a shallow socket called the glenoid cavity which joins the humerus to form a ball-and-socket shoulder joint.

Definition: The glenoid cavity is a shallow socket on the scapula that receives the head of the humerus to form the shoulder joint.

Clavicle (collarbone)

S-shaped bone that connects the scapula to the sternum.
Helps stabilize the shoulder and transmits mechanical force from the limb to the trunk.

💡 Did you know?Fun fact: The clavicle is the most commonly broken bone when people fall onto an outstretched hand or directly onto the shoulder.

Upper Limbs

The upper limb contains six main types of bones arranged from proximal (closer to the trunk) to distal (farther from the trunk):

Humerus — single long bone of the upper arm
Ulna — one of two forearm bones, located on the little-finger side
Radius — the other forearm bone, located on the thumb side
Carpals — eight small bones forming the wrist
Metacarpals — five bones that form the palm
Phalanges — fourteen bones that form the fingers (three per finger except two in the thumb)

Humerus

Long bone extending from the shoulder (articulates with the scapula at the glenoid cavity) to the elbow.
Proximal end forms the ball for the ball-and-socket shoulder joint; distal end articulates with the radius and ulna to form the elbow hinge joint.

Ulna and Radius

Ulna: larger of the two forearm bones, on the little-finger side; has a C-shaped articular surface that fits the humerus to form the elbow hinge.
Radius: thinner bone on the thumb side; distal end articulates with carpal bones to form the wrist joint and allows forearm rotation (supination and pronation).

Carpals, Metacarpals, and Phalanges

Carpals: eight small bones in two rows that allow complex wrist movements.
Metacarpals: five bones forming the palm; numbered I–V from the thumb side.
Phalanges: fourteen bones of the fingers — digits II–V have three phalanges (proximal, middle, distal); the thumb (digit I) has two (proximal, distal).

💡 Did you know?Did you know the arrangement of carpals and the length of metacarpals enable precision grip and manipulation used in tool use and writing?

Comparison: Pectoral vs Pelvic Girdles

Feature	Pectoral Girdle	Pelvic Girdle
Bones	Scapula, clavicle	2 hip bones (ilium, ischium, pubis fused)
Attachment to axial skeleton	Loose, allows wide range of motion	Strong, rigid connection for weight-bearing
Primary function	Mobility of upper limb	Support and transmit weight of body to lower limbs
Joint type at limb connection	Ball-and-socket (shallow socket)	Ball-and-socket (deep socket — acetabulum)

Practical examples and applications

Throwing a ball: uses the hu

FlashcardsKnowledge testSummaryPodcastMindmap

Start for free

Already have an account? Sign in

Appendicular Skeleton

Klíčové pojmy: Appendicular skeleton includes pectoral/pelvic girdles and upper/lower limbs, Pectoral girdle = scapula + clavicle; provides mobility for the arm, Scapula has a glenoid cavity that forms a shallow ball-and-socket joint with the humerus, Clavicle connects scapula to sternum and stabilizes the shoulder, Humerus connects shoulder to elbow and forms part of the elbow hinge, Ulna is on the little-finger side and forms the elbow hinge with the humerus, Radius is on the thumb side and enables wrist articulation and forearm rotation, Carpals (8), metacarpals (5), phalanges (14) form wrist, palm, and fingers respectively, Thumb (digit I) has two phalanges; other fingers have three each, Pectoral girdle favors mobility; pelvic girdle favors stability

## Introduction The appendicular skeleton includes the bones that support the limbs and attach them to the axial skeleton. It is essential for movement, stability, and many daily activities like lifting, walking and grasping objects. > **Definition:** The appendicular skeleton is the part of the skeleton that comprises the pectoral girdle, upper limbs, pelvic girdle and lower limbs, and it connects the limbs to the axial skeleton. ## Overview of the Appendicular Skeleton The appendicular skeleton can be divided into two large groups: 1. **Pectoral girdle and upper limbs** 2. **Pelvic girdle and lower limbs** These girdles act like belts that join the limbs to the axial skeleton and provide attachment points for muscles that control limb movement. ## Pectoral Girdle The pectoral girdle (shoulder region) consists of two bones on each side: - **Scapula (shoulder blade)** — large, flat, triangular bone on the back - **Clavicle (collarbone)** — S-shaped bone at the front ### Scapula (shoulder blade) - Large, flat, triangular bone with a prominent ridge (the spine of the scapula) for muscle attachment. - Slides over the back of the ribs rather than being firmly attached to the axial skeleton. - Has a shallow socket called the **glenoid cavity** which joins the humerus to form a **ball-and-socket** shoulder joint. > **Definition:** The glenoid cavity is a shallow socket on the scapula that receives the head of the humerus to form the shoulder joint. ### Clavicle (collarbone) - S-shaped bone that connects the scapula to the sternum. - Helps stabilize the shoulder and transmits mechanical force from the limb to the trunk. Fun fact: The clavicle is the most commonly broken bone when people fall onto an outstretched hand or directly onto the shoulder. ## Upper Limbs The upper limb contains six main types of bones arranged from proximal (closer to the trunk) to distal (farther from the trunk): - **Humerus** — single long bone of the upper arm - **Ulna** — one of two forearm bones, located on the little-finger side - **Radius** — the other forearm bone, located on the thumb side - **Carpals** — eight small bones forming the wrist - **Metacarpals** — five bones that form the palm - **Phalanges** — fourteen bones that form the fingers (three per finger except two in the thumb) ### Humerus - Long bone extending from the shoulder (articulates with the scapula at the glenoid cavity) to the elbow. - Proximal end forms the ball for the ball-and-socket shoulder joint; distal end articulates with the radius and ulna to form the elbow hinge joint. ### Ulna and Radius - **Ulna**: larger of the two forearm bones, on the little-finger side; has a C-shaped articular surface that fits the humerus to form the elbow hinge. - **Radius**: thinner bone on the thumb side; distal end articulates with carpal bones to form the wrist joint and allows forearm rotation (supination and pronation). ### Carpals, Metacarpals, and Phalanges - **Carpals**: eight small bones in two rows that allow complex wrist movements. - **Metacarpals**: five bones forming the palm; numbered I–V from the thumb side. - **Phalanges**: fourteen bones of the fingers — digits II–V have three phalanges (proximal, middle, distal); the thumb (digit I) has two (proximal, distal). Did you know the arrangement of carpals and the length of metacarpals enable precision grip and manipulation used in tool use and writing? ## Comparison: Pectoral vs Pelvic Girdles | Feature | Pectoral Girdle | Pelvic Girdle | |---|---:|---:| |Bones | Scapula, clavicle | 2 hip bones (ilium, ischium, pubis fused) | |Attachment to axial skeleton | Loose, allows wide range of motion | Strong, rigid connection for weight-bearing | |Primary function | Mobility of upper limb | Support and transmit weight of body to lower limbs | |Joint type at limb connection | Ball-and-socket (shallow socket) | Ball-and-socket (deep socket — acetabulum) | ## Practical examples and applications - Throwing a ball: uses the hu