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Posted by Jim True on November 7, 2006 10:29 PM. Last Updated December 7, 2006 2:24 PM

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APP102: Bones & Bony Landmarks

Functions of the Skeleton

• Movement: lever system that allows for muscular coordination of both motion and posture. Articulation (point where two or more bones meet also known as a joint) greatly determines possible muscular movement.
• Protection: Protects brain, spinal column and vital organs in thoracic cavity.
• Support: Legs are support columns for standing, ribs support chest wall; hips provide support for lower abdominal organs.
• Storage: Fat ("yellow marrow") stored in internal cavity of long bones; matrix of bones connective tissue acts as mineral reservoir for calcium, magnesium and phosphorous.
• Hematopoiesis: Blood formation withing certain long bones (femur & humerus) and in the "red marrow" of flat bones (sternum & hip bones).

Structure of Bones

• Bone is an ORGAN (two or more tissues working together for common function)
• Mostly Connective tissue, but also epithelium, blood, fat & nerves
• Hard Calcified Matrix with LOTS of Collagen
• Calcium - HARD (inorganic)
• Collagen - TOUGH (organic)

Bone Tissue

• Living Tissue with THREE Types of Cells
1. Osteocytes [osteo - bone; cytes - cells]: Mature Bone Cells; maintain the matrix for bone tissue
2. Osteoblasts: Build new bone tissue
3. Osteoclasts: Break down bone tissue
• Together the three bone cells work in harmony to maintain homeostasis; providing minerals and nutrients when needed and growing bone when needed.
• Two Types of Bone tissue:
1. Compact Bone: Outer part of the bone; formed into long, vertical, cylinder shapes that surround tiny hollow cavity where blood vessels reside.
2. Spongy Bone: Resembles sponge; fills in the rest of the bone, inside the compact bone region; leaves room for medulllary cavity in bones that have this part.

Shapes of Bones

• Long Bones
• longer than they are wide
• include all the bones of the limbs, EXCEPT wrist and ankles.
• FIVE Important Parts [figure 6-2, pg 86 in Memmlers]
1. Diaphysis: long narrow part of the bone; sometimes called the "shaft"
2. Epiphyses: Enlarged ends at either end of diaphysis; Singular is called epiphysis. Proximal epiphysis & distal epiphysis at proximal and distal ends of diaphysis. EPI means "on top of"
3. Epiphyseal line: Structure that penetrates the bone in both epiphyses. Made of Hyaline cartilage during growing years. Bone growth occurs here until it stops when line ossifies (hardens).
4. Periosteum: epithelium covering over whole bone EXCEPT at both ends where there is cartilage. Muscle tendons & ligaments attach to it.
5. Medullary cavity: hollow cavity inside diaphysis; filled with tissue called marrow; hematopoiesis occurs here.
• Short Bones: cube-like shape; ONLY in bones in wrist and ankle. Spongy bone surrounded by compact bone. NO medullary cavity.
• Flat Bones: thin, flat and slightly curved. Most Skull bones, ribs, sternum; hematopoiesis occurs in some of them.
• Irregular Bones: refuse to be easily classified. Vertebrae, scapula, hip bones and some skull bones.
• Sesamoid Bones: bones developed and embedded completely inside a tendon. Patella (knee-cap)

Bony Landmarks

• Landmarks: bumps, grooves, and holes that muscles attach to and nerves and blood vessels pass through.
• NINE Projections: sick out from the main part of the bone and are USUALLY where muscles are attached.
1. Process: finger-like projection sticks out quite away from the main part of the bone. (sharp,
2. Condyle: Large round protuberance at end of a bone that helps forms a joint.
3. Epicondyle: epiphyseal ends of the long bones; ALWAYS lateral and medial (epi - ABOVE Condyle)
4. Head: Rounded PROXIMAL end of bone.
5. Crest: Prominent ridge on a bone, often anterior
6. Line: Less prominent ridge on a bone, often posterior
7. Tubercle: Small bump.
8. Tuberosity: Medium-sized bump, but some of them are hardly noticeable; just a swollen area on the bone.
9. Trochanter: Large bump; only TWO of them on the femur.
• THREE Holes and Depressions: used for passage of blood vessels, nerves and other soft tissues and can only be used for muscle attachment.
1. Foramen: Hole through the hole bone, or just into the center of the bone. Plural is foramina
2. Fossa: shallow depression on a bone, a "scooped out" area.
3. Meatus: Canal or tube like opening that penetrates inside a bone.

Divisions of the Skeleton

• TWO Divisions of the Skeleton:
1. Axial Bones of the body's axis, trunk and vertebral column and hyoid bone
2. Appendicular: bones of the appendages and the 'girdles' that are used to attach them to the axial skeleton

AXIAL Skeleton (80 bones)

• SKULL (pg. 234, 235 in Trail Guide; 90, 93 in Memmlers)
• 22 bones in the SKULL, excluding the bones of the inner ear (ear ossicles);
• We'll be learning 4 of the cranial and 3 of the facial bones
• joined by sutures, which are tight fitting joints that connect the bones of the skull.
• Cranial Bones (4)
1. Frontal Bone. divide the cranium along the coronal plane; this is the Coronal Suture.The bone in front is the Frontal Bone.
2. Parietal Bones (2): Behind the Coronal suture are a pair of bones split sagitally along the Sagittal Suture. These are the Parietal Bones.
3. Temporal Bones(2): Below these and coming down around the ears are the Temporal Bones.
4. Occipital Bone: Behind the cranium and joined to the parietal bones by the Lambdoidal Suture (think the Greek Lambda character, Λ), is the Occipital Bone..
• Important landmarks on the Cranial Bones:
• Occipital protubrence: large bump in the middle of the occipital bone.
• Occipital Ridge: raised ride along the bottom of the occipital bone.
• Foramen Magnum: large hole in the bottom of the occipital bone that spinal cord attached to the the brain through.
• Mastoid Processes: bony protuberance sticking off of the temporal bone behind both ears.
• TemporoMandibular Joint: Joint formed at the joining of the Temporal bone and the Mandible (jawbone); TMJ for short.
• External Auditory Meatus: hole in the Temporal bone for the Ear Canal.
• Facial Bones (3):
1. Mandible the jawbone.
2. Maxilla: above the jawbone, upper mouth.
3. Zygomatic Bone (2): these form the cheekbones and attach to the Temporal Bones; the sloping curve is the Zygomatic arch
• VERTEBRAL COLUMN (Spine) (pg 176-178 in Trail Guide; 92-95 Memmlers)
• 26 vertebrae; 24 are TRUE Vertebrae (see below).
• Supports the head, transmits the weight of the upper body to the lower limbs, protects the spinal cord, provides attachment for muscles of the back.
• FOUR Curvatures: (sections of the spine indicated by a change in curve and a change in type of vertebral bone
1. Cervical (concave) Lordosis
2. Thoracic (convex) Kyphosis
3. Lumbar (concave) Lordosis
4. Sacral (concave) Kyphosis
• Concave (caves away from you when looking at the spine posteriorly). Convex curves toward you.
• Scoliosis: unnatural curve from midline laterally
• Lordosis (concave) - normal developmental curve.
• Kyphosis (convex), curves posteriorly backward.
• Vertebrae are NUMBERED starting at 1 within each region.
• Cervical has 7 (breakfast at 7), C1-C7
• Thoracic has 12 (lunch at 12), T1-T12
• Lumbar has 5 (dinner at 5), L1-L5
• Sacrum & Coccyx (2 - Sacral)
• True Vertebrae are Cervical through Lumbar; Sacrum & Coccyx are FALSE vertebrae. Sacrum are fused bones.
• Atlas is C1 (allows YES movement), Axis is C2 (allows for NO movement)
• Vertebral Landmarks
  • Body: large part of the vertebra that looks like tree stump; intervertebral discs attach to these.
  • Spinous process: spiny projection that sticks out toward the back of the body (posteriorly)
  • Transverse process: spiny projections that stick out to the sides of the vertebrae (laterally)
  • Lamina groove: gully on either side of the spinous process
  • Vertebral foramen: large hole for spinal cord. When all the vertebrae are stacked up together the channel created is the spinal canal which houses the Spinal Cord.
  • Transverse foramen: Holes in the transverse processes. Two or more are called 'formamina'; ie Transverse Foramina
  • Intervertebral foramen: when two vertebrae are stacked together they line up to form a hole on the lateral aspect. This is where the spinal nerves pass out to the body from the spinal cord.
• Tricks to Identifying Different Vertebrae
• CERVICAL Vertebrae
1. Transverse Foramen (holes on the sides)
2. TRIANGULAR shaped Vertebral Foramn (main hole for spine)
3. BODY small and delicate
4. SPINOUS process is forked in 2 directions (bifid)
• ATLAS (C1)
1. NO Body and NO Spinous Process
• AXIS (C2)
1. Body and Spinous process
2. Dens of Axis: process that sticks upwards and fits into the vertebral foramen of the ATLAS. Joint allows the Atlas to rotate around the dens and gives us the NO gesture.
• THORACIC Vertebrae
1. ROUND Vertebral Foramen
2. BODY medium sized
3. SPINOUS Process angles downward (inferiorly angled)
• LUMBAR Vertebrae
1. TRIANGULAR, smaller Vertebral foramen
2. BODY large and chunky
3. SPINOUS process large and pointy
• THORACIC RIB CAGE (p. 179 in Memmlers)
• Consist of the thoracic vertebrae in back, the ribs on the side and the sternum in front
• Protects the heart and the lungs
• Provides attachment for SHOULDER GIRDLE (Clavicle & Scapula)
• TWELVE Pairs of Ribs, defined by how they attach to the STERNUM if at all
• TRUE Ribs (1-7): first Seven ribs attaching directly to Sternum by Costal cartilage
• FALSE Ribs (8-10), next three connect to sternum indirectly by connecting to #7 with costal cartilage
• FLOATING Ribs (11 & 12), no connection to the sternum, just float in space.
• Sternum: anterior connection for the ribs and provides protection to the heart. THREE parts
1. Manubrium: TOP of sternum, triangular shaped, connects to the Clavicle. Important landmark is the:
   Suprasternal notch, indentation on the TOP (Superior aspect), SUPRA = 'top or above', so Suprasternal, 'above sternum'
2. Body: main, middle part of the sternum
3. Xiphoid Process: bottom inferior part of the sternum; used in CPR to determine where to press for heart compressions and can be easily broken off.

APPENDICULAR Skeleton (126 bones)

• ONLY Bony Attachment to AXIAL Skeleton is at the SternoClavicular Joint (where Sternum connects to the Clavicle)
• SHOULDER GIRDLE
• Clavicle
• Acomial End - lateral end; attachment point for scapula at Acromion Process
• Sternal End - medial end; attachment point for sternum
• Scapula
• Spine of the Scapula
• Acromion process
• Coracoid process
• Glenoid cavity
• Supraspinous fossa: SUPRA means ABOVE, "Above the spine"
• Infraspinous fossa: INFRA means BELOW, "Below the Spine"
• Subscapular fossa: SUB means UNDERNEATH "Underneath the Spine"
• Medial and Lateral Borders: These are the flat sides Medial (or towards the Vertebrae, so sometimes called Vertebral Border) and towards the outside of the body or Lateral Border
• Superior and Inferior Angles
• The UPPER LIMBS
• Humerus (ARM)
• Head
• Greater Tubercle
• Lesser Tubercle
• Intertubercular Groove
• Deltoid Tuberosity
• Olecranon fossa
• Medial & Lateral Epicondyles
• Ulna (FOREARM): Little finger side
• Olecranon process
• Coronoid process
• Radius: thumb side, radiates (rotates) around the Ulna
• Head
• Radial Tuberosity
• Styloid process of the Radius
• Carpals (8 bones, the WRIST)
• Metacarpals (5 bones, the HAND), META means 'Distal To', so the MetaCarpals are 'Distal to the Carpals'
• #'d 1-5 from thumb to little finger (lateral to medial)
• Phalanges, the FINGERS
• (14 bones, 3 each for the fingers (12) and 2 for the thumb)
• #'d 1-5 from thumb to little finger
• bone closest to the hand is proximal, middle and then distal
• thumb has no middle phalange.
• PELVIC GIRDLE(the Hips)
• Coxal Bones (2 of 'em)
• Formed of Three Bones that fuse together after being born.
1. Ilium (superior): this is the large part of the hip
2. Ischium (inferior): the lower part of the hip (the tailbone)
3. Pubis (anterior): the pubic bone where it joins in front to the other coxal bone
• Important Coxal Bone Landmarks
• Acetabulum: The hip socket where the femur attaches. Always lateral on each coxal bone.
• Greater Sciatic Notch: Posterior aspect of the ilium just in front of the last part of the Iliac crest. Outlet for the sciatic nerve.
• Iliac Fossa: Anterior aspect of the ilium, large scooped out area.
• Obturator foramen: The large hole in the coxal bone; this is covered by membrane in a human being so it's obscured; 'obturator' means obscured.
• Iliac Spine: huge bony ride that goes from the front of the ilium all the way to the back and ends at the greater sciatic notch. Four major landmarks on this crest, named by location and position (ie superior/inferir and anterior/posterior), from Front to Back:
1. Anterior Inferior Iliac Spine (AIIS)
2. Anterior Superior Iliac Spine (ASIS)
3. Posterior Superior Iliac Spine (PSIS)
4. Posterior Inferior Iliac Spine (PIIS)
• Ischial Tuberosity: large ridge bump on the bottom of coxal bones (the iscium); often called the SITS because they support all of our weigh when we sit down; the gluteal muscles move out of the way when we sit and these support our body weight. Hamstrings also attach here.
• Pubic symphysis: the joint between the left and right coxal bones. This is the ONLY attachment point for the two hip bones (sacrum lies between the bones in back). This joint is formed of fibrocartilage just like the intervertebral discs.
• Superior Pubic Ramus: Ramus means 'bridge' this is the thin bony bridge that runs from the pubic symphysis to the aceteabulum. The bone ABOVE the hole (obturator foramen).
• Inferior Pubic Ramus: the bridge of bone BELOW the Obturator Foramen that runs from the pubic symphysis to the ischial tuberosity.
• Gender Differences apparent in the Coxal Bones
• The LOWER LIMB
  • Femur (THIGH)
  • Head
  • Neck
  • Greater Trochanter
  • Lesser Trochanter
  • Gluteal Tuberosity
  • Linea aspera
  • Medial & Lateral epicondyles
  • Patellar surface
  • Patella (KNEE)
  • Tibia (LEG): Medial side of the Leg
  • Tibial tuberosity
  • Crest
  • Medial and Lateral Condyles
  • Pes anserinus: means 'goose feet' because the muscles that attach here look like goose feet. Medial side on distal to medial condyle where the curve straightens.
  • Medial malleolus: projects past the bones of the ankle to create a notch for the ankle joint. Medial side.
  • Fibula: lateral side of the leg
  • Head
  • Lateral Malleolus: creates the other side of the notch for the ankle joint on the lateral side of the leg.
  • Tarsals (7 bones, the ANKLE)
  • Talus: Most superior, usually called the ankle bone as this large bone fits into the notch formed by the medial and lateral malleolus and supports the weight of the body and then distributes it further down to the bones of the ankle and foot.
  • Calcaneus: Most Posterior bone of the foot; the heel bone.
  • Metatarsals (5 bones, the FOOT)
  • Phalanges, the TOES

Disclaimer: These are MY notes taken from classroom lectures while I'm in the classroom. While I'm perfectly happy to share my notes with my classmates and I know I take very good notes, you should still make every effort to attend the class and TAKE YOUR OWN NOTES. I will not transcribe everything the instructor says in the classroom, and I will NEVER post pre-exam reviews. My notes will not replace the value of actually attending class and taking your own class notes.I also cannot attest to their accuracy, other than they are what was provided in the lecture; you should not reference my notes as "expert opionion" by any means, and if you notice an error or omission, please do me the favor of e-mailing me with the correction and I will re-post my notes. End of Disclaimer.