Study Guide: The Skeleton – Anatomy & Physiology Chapter 7

The Skeleton: Overview and Major Bones

Introduction

The human skeleton provides the structural framework for the body, protects vital organs, and enables movement. Understanding the names, locations, and functions of bones is fundamental in anatomy and physiology.

Major Bones of the Skull

• Frontal bone: Forehead region.

• Temporal bone: Located behind the ear.

• Parietal bone: Sides of the skull, directly above the ears.

• Occipital bone: Back of the head, forms the posterior skull base.

• Ethmoid bone: Inside the cranial cavity, behind the tear duct.

• Maxilla: Upper jaw, forms part of the orbit and nasal cavity.

• Mandible: Lower jaw, only movable bone of the skull.

• Zygomatic bone: Cheekbone, lateral to the maxilla.

• Vomer bone: Forms part of the nasal septum.

• Malleus, incus, stapes: Auditory ossicles, smallest bones in the body, located in the middle ear.

Major Bones of the Upper and Lower Limbs

• Clavicle: Collar bone, connects sternum to scapula.

• Scapula: Shoulder blade, located on the upper back.

• Humerus: Upper arm bone.

• Radius: Lateral bone of the forearm (thumb side).

• Ulna: Medial bone of the forearm (pinky side).

• Carpals: Wrist bones (8 small bones).

• Femur: Thigh bone, longest and strongest bone in the body.

• Patella: Kneecap.

• Tibia: Medial bone of the lower leg (shin bone).

• Fibula: Lateral bone of the lower leg.

• Tarsals: Ankle bones.

Spinal Column and Curvatures

Regions of the Spinal Column

The vertebral column is divided into five regions, each with distinct characteristics and functions:

1. Cervical (7 vertebrae): Neck region, supports the head.

2. Thoracic (12 vertebrae): Upper/mid-back, articulates with ribs.

3. Lumbar (5 vertebrae): Lower back, bears most body weight.

4. Sacral (5 fused vertebrae): Forms the sacrum, part of the pelvis.

5. Coccyx (3-5 fused vertebrae): Tailbone.

Abnormal Spinal Curvatures

Abnormal curvatures of the spine can affect posture and health. The three main types are:

Name of Curvature	Description/Appearance	Cause
Scoliosis	Lateral (sideways) curvature of the spine	Often idiopathic, can be congenital or due to neuromuscular conditions
Kyphosis	Hunchback; exaggerated thoracic curvature	Common in elderly due to osteoporosis
Lordosis	Swayback; exaggerated lumbar curvature	Pregnancy, obesity, or compensatory for abdominal mass

Bone Acronyms and Mnemonics

Carpal Bones (Wrist)

Mnemonic: "Squirrels Love To Play Tag, Then Chase Humans." (Scaphoid, Lunate, Triquetrum, Pisiform, Trapezium, Trapezoid, Capitate, Hamate)

Tarsal Bones (Ankle)

Mnemonic: "Crazy Timmy Never Could Make Ice Cream Last." (Calcaneus, Talus, Navicular, Cuboid, Medial cuneiform, Intermediate cuneiform, Lateral cuneiform)

Pelvic Girdle and Pelvis

Pelvic Girdle

• Composed of two coxal bones (each made of ilium, ischium, and pubis) and the sacrum.

• The pelvis includes the pelvic girdle plus the coccyx.

Differences Between Male and Female Pelvis

• Female pelvis is wider, shallower, lighter, and rounder for childbirth.

• Female pubic arch is broader.

• Male pelvis is more robust and narrower.

Infant vs. Adult Skull

Key Differences

• Infant cranium is large relative to the face.

• Mandible and frontal bones are not fused in infants.

• Maxilla and mandible are underdeveloped; facial contours are flatter.

• Fontanelles (soft spots) are present in infants, allowing for brain growth.

Bone Identification and Terminology

Common Anatomical Terms

• Funny bone: Ulnar nerve, runs behind the medial epicondyle of the humerus.

• Phalanges: Bones of the fingers and toes.

• Coccyx: Tailbone, composed of fused vertebrae.

Vocabulary and Bone Features

Key Terms and Definitions

Vocab Term	Definition	Example/Use	Synonym
Sesamoid bone	A bone embedded within a tendon	Patella (kneecap)	Stress-induced bone
Suture	Immovable joint between skull bones	Coronal suture between parietal and frontal bones	Joint, seam
Foramen	Opening or hole in a bone for nerves/vessels	Foramen magnum in the skull	Hole, passage
Sinus	Cavity within a bone	Maxillary sinus	Cavity, hollow
Fontanelle	Soft spot on infant skull	Anterior fontanelle	Soft spot
Scoliosis	Lateral curvature of the spine	"S"-shaped back	Curved spine

Additional Info

• Strongest bone in the body: The femur, capable of withstanding significant force.

• Pelvic girdle vs. pelvis: The pelvic girdle refers to the two hip bones; the pelvis includes the sacrum and coccyx as well.

• Bone fusion in infants: Fontanelles allow for brain growth and facilitate childbirth.