Surface Anatomy
The surface anatomy of this region may be studied on a living subject or on the cadaver. In the cadaver, fixation may make it difficult to distinguish bone from well-preserved soft tissues.
Turn the cadaver to the prone position (face down) and palpate the following structures (Fig. 1.01)
The surface anatomy of this region may be studied on a living subject or on the cadaver. In the cadaver, fixation may make it difficult to distinguish bone from well-preserved soft tissues.
Turn the cadaver to the prone position (face down) and palpate the following structures (Fig. 1.01)
KEY TO REFERENCES
G = Grant’s Atlas, 11th ed., page number
N = Netter’s Atlas, 3rd ed., plate number
R = Rohen’s Color Atlas of Anatomy, 5th ed., page number
C = Clemente’s Atlas, 4th ed., page number
G = Grant’s Atlas, 11th ed., page number
N = Netter’s Atlas, 3rd ed., plate number
R = Rohen’s Color Atlas of Anatomy, 5th ed., page number
C = Clemente’s Atlas, 4th ed., page number
Skeleton of the Back
Refer to a skeleton. On the scapula, identify (Fig. 1.02): [G 459;
N 404; R 359; C 70]
• Acromion
• Spine
• Superior angle
• Medial (vertebral) border
• Inferior angle
On the ilium, identify (Fig. 1.02): [G 299; N 152; R 184; C 249]
• Iliac crest
• Posterior superior iliac spine
On the occipital bone, identify (Fig. 1.02):
• External occipital protuberance (inion)
• Superior nuchal line
On the temporal bone, identify (Fig. 1.02):
• Mastoid process
Refer to a skeleton. On the scapula, identify (Fig. 1.02): [G 459;
N 404; R 359; C 70]
• Acromion
• Spine
• Superior angle
• Medial (vertebral) border
• Inferior angle
On the ilium, identify (Fig. 1.02): [G 299; N 152; R 184; C 249]
• Iliac crest
• Posterior superior iliac spine
On the occipital bone, identify (Fig. 1.02):
• External occipital protuberance (inion)
• Superior nuchal line
On the temporal bone, identify (Fig. 1.02):
• Mastoid process
The vertebral column (Fig. 1.02) consists of 33 vertebrae: 7
cervical (C), 12 thoracic (T), 5 lumbar (L), 5 sacral (S), and 4
coccygeal (Co). The upper 24 vertebrae (cervical, thoracic, and
lumbar) allow flexibility and movement of the vertebral column,
whereas the sacral vertebrae are fused to provide rigid support of
the pelvic girdle. A typical thoracic vertebra will be described,
and the cervical and lumbar vertebrae will be compared to it.
[G 276; N 146; R 189; C 422]
Refer to a disarticulated thoracic vertebra and identify (Fig.
1.03): [G 286; N 147; R 186; C 423]
• Body
• Vertebral arch – formed by the combination of pedicles and
laminae
• Pedicle (2)
• Lamina (2)
• Vertebral foramen
cervical (C), 12 thoracic (T), 5 lumbar (L), 5 sacral (S), and 4
coccygeal (Co). The upper 24 vertebrae (cervical, thoracic, and
lumbar) allow flexibility and movement of the vertebral column,
whereas the sacral vertebrae are fused to provide rigid support of
the pelvic girdle. A typical thoracic vertebra will be described,
and the cervical and lumbar vertebrae will be compared to it.
[G 276; N 146; R 189; C 422]
Refer to a disarticulated thoracic vertebra and identify (Fig.
1.03): [G 286; N 147; R 186; C 423]
• Body
• Vertebral arch – formed by the combination of pedicles and
laminae
• Pedicle (2)
• Lamina (2)
• Vertebral foramen
• Transverse process (2)
• Transverse costal facet
• Spinous process
• Articular processes – superior and inferior
• Vertebral notches – superior and inferior
• Costal facets – superior and inferior
The spinous process of a thoracic vertebra is long, slender, and directed inferiorly over the spinous process of the vertebra that is inferior to it. Articulation with ribs is a unique character-
istic of thoracic vertebrae. The head of a rib articulates with the bodies of two adjacent vertebrae (Fig. 1.04). The tubercle of a rib articulates with the transverse costal facet of the thoracic ver-tebra of the same number (i.e., the tubercle of rib 5 articulates with the transverse costal facet of vertebra T5). An interverte-bral disk and the articular processes unite two adjacent verte-brae. The vertebral notches of two adjacent vertebrae combine to form an intervertebral foramen. A spinal nerve passes through the intervertebral foramen.
Cervical vertebrae differ from thoracic vertebrae in the fol-lowing ways (Fig. 1.05): cervical vertebrae have smaller bodies, larger vertebral foramina, shorter spinous processes that bifur-
cate at the tip, and transverse processes that contain a foramen transversarium. On an articulated skeleton, identify the follow-ing features common to all cervical vertebrae: [G 284; N 15;
R 186; C 418]
• Transverse process
• Foramen transversarium
• Spinous process
On a skeleton, observe the following features of individual
cervical vertebrae:
• Atlas (C1) – does not have a body.
• Axis (C2) – has the dens, which is the body of C1 that has
become fused to C2 during development.
• Vertebra prominens (C7) – has the most prominent spinous
process in the cervical region, hence its name.
Lumbar vertebrae differ from thoracic vertebrae in the fol-lowing ways (Fig. 1.05): lumbar vertebrae have larger bodies, broad spinous processes that project posteriorly, and they do not have articular facets for ribs. On a skeleton, observe the lumbar vertebrae and notice that their spines do not overlap like the spines of thoracic vertebrae. [G 289; N 148; R 186; C 426] The sacrum is formed by five fused vertebrae and it does not have identifiable spines or transverse processes. On the dorsal surface of the sacrum, identify (Fig. 1.06): [G 293; N 150; R 187; C 428]
• Median sacral crest
• Posterior (dorsal) sacral foramina
• Sacral hiatus
The coccyx is a small triangular bone formed by four rudi-
mentary coccygeal vertebrae that are fused together (Fig. 1.06).
• Transverse costal facet
• Spinous process
• Articular processes – superior and inferior
• Vertebral notches – superior and inferior
• Costal facets – superior and inferior
The spinous process of a thoracic vertebra is long, slender, and directed inferiorly over the spinous process of the vertebra that is inferior to it. Articulation with ribs is a unique character-
istic of thoracic vertebrae. The head of a rib articulates with the bodies of two adjacent vertebrae (Fig. 1.04). The tubercle of a rib articulates with the transverse costal facet of the thoracic ver-tebra of the same number (i.e., the tubercle of rib 5 articulates with the transverse costal facet of vertebra T5). An interverte-bral disk and the articular processes unite two adjacent verte-brae. The vertebral notches of two adjacent vertebrae combine to form an intervertebral foramen. A spinal nerve passes through the intervertebral foramen.
Cervical vertebrae differ from thoracic vertebrae in the fol-lowing ways (Fig. 1.05): cervical vertebrae have smaller bodies, larger vertebral foramina, shorter spinous processes that bifur-
cate at the tip, and transverse processes that contain a foramen transversarium. On an articulated skeleton, identify the follow-ing features common to all cervical vertebrae: [G 284; N 15;
R 186; C 418]
• Transverse process
• Foramen transversarium
• Spinous process
On a skeleton, observe the following features of individual
cervical vertebrae:
• Atlas (C1) – does not have a body.
• Axis (C2) – has the dens, which is the body of C1 that has
become fused to C2 during development.
• Vertebra prominens (C7) – has the most prominent spinous
process in the cervical region, hence its name.
Lumbar vertebrae differ from thoracic vertebrae in the fol-lowing ways (Fig. 1.05): lumbar vertebrae have larger bodies, broad spinous processes that project posteriorly, and they do not have articular facets for ribs. On a skeleton, observe the lumbar vertebrae and notice that their spines do not overlap like the spines of thoracic vertebrae. [G 289; N 148; R 186; C 426] The sacrum is formed by five fused vertebrae and it does not have identifiable spines or transverse processes. On the dorsal surface of the sacrum, identify (Fig. 1.06): [G 293; N 150; R 187; C 428]
• Median sacral crest
• Posterior (dorsal) sacral foramina
• Sacral hiatus
The coccyx is a small triangular bone formed by four rudi-
mentary coccygeal vertebrae that are fused together (Fig. 1.06).
